- Ifeffit - millenia.cars.aps.anl.gov

How to normalize tens of thousands of XAS data?
by 张驰 15 Nov '22

15 Nov '22

How to normalize tens of thousands of XAS data? I measured a series of the spectra of sample over time by in situ XAS, the results contained tens of thousands of sets of XAS data, and it was impossible to normalize each set of data individually.I would like to ask where to find the normalized source code of Athena, I can modify the code so I can use my computer to achieve a large number of processing.Thanks!

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found some issues found in larch (read-in issues)
by Mangold, Stefan (IPS) 26 Oct '22

26 Oct '22

Dear All, dear Matt, all tests were done on Macs (one M1 & one Intel) with the latest version your software & latest OS. 1. Read-In of spec files works, but only one file at once. Even if multiple files are selected 2. If one tries to load text-files it is possible to load data form multiple files as long as you don’t try to load also the reference spectra. If you load the reference also the read-in stopps at the transmission/fluorescence spectrum of the second file selected. 3. Trouble, that I sometimes can’t unmount network volumes after reading from them, larch saved on local discs. MacOS claims that python has files open; no other python program running 4. unable to save the data of one XAS-viewer while having two xas-viewer open. best regards Stefan Mangold

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Xraylarch installation
by Dien.Li＠srnl.doe.gov 14 Oct '22

14 Oct '22

Dear Matt With help of our IT folk, we downloaded Larch for windows binary installer file and installed the xraylarch 9.65 on my computer, however, the LARCH subdirectory with the five application platforms (e.g., XAS viewer) were NOT generated automatically. We tried to uninstall and install three times, it is still the same, could you please suggest what we may do to correct this? Thank you so much. Dien Li Savannah River National Laboratory

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[Larch] S02 value larger than 1
by dxfan＠post.kek.jp 04 Oct '22

04 Oct '22

Dear All, � I have a very common question, which is already asked many times: the S02 value is larger than 1. I measure the Sr K-edge EXAFS of SrTiO3 with temperature dependence. The S02 value is larger than 1. I check the book of “XAFS for everyone”, in which say maybe because of the distorted data or wrong structure model. I check the data measured by other beamline with the same sample, the S02 value still is larger than 1. I change the background reduction parameters, same result. I also modify the model, still same result. � I am very confused with these results. I attached the data, FEFF paths, and the fitting python Code the package. Can anyone help me check my fitting procedure. � Best regards, Fan

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Co2P spectrum
by Christian Wittee Lopes 21 Sep '22

21 Sep '22

Dear XAFS community, Does anyone have a spectrum of Co2P sample or standard? Thank you in advance. Best, Christian Wittee Lopes -- Christian Wittee Lopes Visiting Researcher - ANP/FINEP - PRH 50.1 Institute of Chemistry, Universidade Federal do Rio Grande do Sul (UFRGS) chriswittee(a)gmail.com LinkedIn <https://www.linkedin.com/in/christian-wittee-lopes-561855219/> | ORCID <https://orcid.org/my-orcid?orcid=0000-0001-8420-1958> | Lattes <http://lattes.cnpq.br/4953371870936050>

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Re: [Ifeffit] [EXTERNAL] Ifeffit Digest, Vol 235, Issue 12
by Dien.Li＠srnl.doe.gov 15 Sep '22

15 Sep '22

HI, Matt Attached please find the raw data in Athena, could you please also look at this as well as the Artemis file. Due to limited by L1,2 edge, the EXAFS data may just go up to K 9. Anyhow, thank you so much for your any directions. Dien Li -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Thursday, September 15, 2022 2:09 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 12 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 11 (Dien.Li(a)srnl.doe.gov) ---------------------------------------------------------------------- Message: 1 Date: Thu, 15 Sep 2022 18:04:42 +0000 From: "Dien.Li(a)srnl.doe.gov" <Dien.Li(a)srnl.doe.gov> To: "ifeffit(a)millenia.cars.aps.anl.gov" <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] [EXTERNAL] Ifeffit Digest, Vol 235, Issue 11 Message-ID: <DM8PR09MB6232238674FEDB80096B6498C4499(a)DM8PR09MB6232.namprd09.prod.outlook.com> Content-Type: text/plain; charset="us-ascii" Please see this attachment. Thank you so much. Dien -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Thursday, September 15, 2022 1:42 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 11 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 (Dien.Li(a)srnl.doe.gov) ---------------------------------------------------------------------- Message: 1 Date: Thu, 15 Sep 2022 17:41:19 +0000 From: "Dien.Li(a)srnl.doe.gov" <Dien.Li(a)srnl.doe.gov> To: "ifeffit(a)millenia.cars.aps.anl.gov" <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 Message-ID: <DM8PR09MB6232C4DEDD6CCE2CF3984655C4499(a)DM8PR09MB6232.namprd09.prod.outlook.com> Content-Type: text/plain; charset="us-ascii" Hi, Matt and EXAFS experts Thank you so much. Our sample is porous silica + PO4 ligand on surface/pore, then react with LaNO3 in solution. The model is that La is bonding with PO4 through both mono- (corner-sharing) and di-dentate (edge sharing) modes. Please see the attachment. The first three fits in history are fits with increasing paths, with fixed CN for the La-P11 and La-P14 path, the ss parameters are reasonable, but to fix CN at 3 for La-P14 is unreasonable, which requires La to bind with three different PO4 groups. The last three fits are fits with increasing paths, in which CN was fitted, the fitted parameters are reasonable, EXCEPT for the negative ss parameters for the path La-P11 (edge sharing) and La-P14 (corner sharing). By the way, the length for La-P14 is +0.3 A, it is large, but not completely unreasonable, because the bond distances of La-O polyhedron may change from 2.4 to 3.1 A. Is it possible to constrain ss parameter? If so, how to set up this constrain? Thank you so much for your further instruction. Dien -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Wednesday, September 14, 2022 4:03 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: Larch: Fitting error of the objective/model function (Matt Newville) 2. Re: Help for EXAFS fitting (Matt Newville) ---------------------------------------------------------------------- Message: 1 Date: Wed, 14 Sep 2022 13:28:38 -0500 From: Matt Newville <newville(a)cars.uchicago.edu> To: XAFS Analysis using Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] Larch: Fitting error of the objective/model function Message-ID: <CA+7ESbodGVSNHuzTHZoeb3iL-jUsWFpeYM7TqLQPkkSyMyE2DA(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hi Fan, Sorry for the trouble. That seems like a strange error to me - I don't see why changing those expressions for E0s (even if they are "slightly complicated"!) should generate NaNs or Infinities. I don't think I've seen that happen with "feffit" fittings. Can you send me a Larch Session File with this fit in it? One suggestion is to place bounds (say +/- 20 eV) on those Parameters, say pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr', min=-20, max=20) But I'm not certain whether that would solve this problem. On Wed, Sep 14, 2022 at 7:53 AM <dxfan(a)post.kek.jp> wrote: > Dear All > > > > I am doing Temperature-dependent EXAFS experiment with a lot of data. > > > > Usually, we do these kinds of data fitting by several steps, like below: > > First, put every parameter free, and obtain the averaged value of amp. > > Second, set the amp to the averaged value, put other parameters free, and > then obtain the averaged value of del_e0. > > Third, set the amp and del_e0 to the averaged value, and fit again. > > > > In my case, my sample is perovskite structure (Ti K-edge of SrTiO3). > > To increase the fitting accuracy, I use three del_e0 for O, Ti, Sr as > suggested in paper: Haskel, D., et al. Physica B: Condensed Matter 208 > (1995): 151-153. > > The fitting parameters of Cubic model is this: > > setattr(pars, f'alpha', param(0, vary=True)) > > setattr(pars, f'amp', param(0, vary=True)) > > setattr(pars, f'del_e0_O', param(0, vary=True)) > > setattr(pars, f'del_e0_Sr', param(0, vary=True)) > > setattr(pars, f'del_e0_Ti', param(0, vary=True)) > > setattr(pars, f'sig2_O', param(.002, vary=True)) > > setattr(pars, f'sig2_Sr', param(.002, vary=True)) > > setattr(pars, f'sig2_Ti', param(.002, vary=True)) > > setattr(pars, f'sig2_Tr1', param(.002, vary=True)) > > setattr(pars, f'sig2_p', param(.002, vary=True)) > > setattr(pars, f'sig2_Tr2', param(.002, vary=True)) > > > > #del_e0 for each path > > pars.del_e0_1=param(expr='del_e0_O') > > pars.del_e0_2=param(expr='del_e0_O') > > pars.del_e0_3=param(expr='del_e0_Sr') > > pars.del_e0_4=param(expr='del_e0_Ti') > > pars.del_e0_5=param(expr='del_e0_O') > > pars.del_e0_6=param(expr='0.5*del_e0_O+0.5*del_e0_Ti') > > pars.del_e0_7=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_8=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_9=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_10=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr') > > > > In the first step, the fitting is fine, I obtained the averaged amp. > > However, in the second step, when I set amp to the averaged value, Error > happens for ?some? of the data. > > When I use different averaged amp value, the data that happens error is > different. > > The error is: > > Traceback (most recent call last): > > File "STO16_C_2.py", line 250, in <module> > > out = feffit(pars, dset) > > File > "D:\anaconda3\envs\xraylarch\lib\site-packages\larch\xafs\feffit.py", line > 557, in feffit > > result = fit.leastsq() > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 1689, in leastsq > > lsout = scipy_leastsq(self.__residual, variables, **lskws) > > File > "D:\anaconda3\envs\xraylarch\lib\site-packages\scipy\optimize\minpack.py", > line 423, in leastsq > > retval = _minpack._lmdif(func, x0, args, full_output, ftol, xtol, > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 601, in __residual > > return _nan_policy(np.asarray(out).ravel(), > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 2436, in _nan_policy > > raise ValueError(msg) > > ValueError: NaN values detected in your input data or the output of your > objective/model function - fitting algorithms cannot handle this! Please > read > https://lmfit.github.io/lmfit-py/faq.html#i-get-errors-from-nan-in-my-fit-w… > for more information. > > > > I don?t know what happened, can somebody help me figure this out? > > > > PS: when I use only one del_e0 for every path, no such error happens. > > > > Best regards > > Fan > _______________________________________________ > Ifeffit mailing list > Ifeffit(a)millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit > -- --Matt Newville <newville at cars.uchicago.edu> 630-327-7411

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Re: [Ifeffit] [EXTERNAL] Ifeffit Digest, Vol 235, Issue 11
by Dien.Li＠srnl.doe.gov 15 Sep '22

15 Sep '22

Please see this attachment. Thank you so much. Dien -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Thursday, September 15, 2022 1:42 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 11 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 (Dien.Li(a)srnl.doe.gov) ---------------------------------------------------------------------- Message: 1 Date: Thu, 15 Sep 2022 17:41:19 +0000 From: "Dien.Li(a)srnl.doe.gov" <Dien.Li(a)srnl.doe.gov> To: "ifeffit(a)millenia.cars.aps.anl.gov" <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 Message-ID: <DM8PR09MB6232C4DEDD6CCE2CF3984655C4499(a)DM8PR09MB6232.namprd09.prod.outlook.com> Content-Type: text/plain; charset="us-ascii" Hi, Matt and EXAFS experts Thank you so much. Our sample is porous silica + PO4 ligand on surface/pore, then react with LaNO3 in solution. The model is that La is bonding with PO4 through both mono- (corner-sharing) and di-dentate (edge sharing) modes. Please see the attachment. The first three fits in history are fits with increasing paths, with fixed CN for the La-P11 and La-P14 path, the ss parameters are reasonable, but to fix CN at 3 for La-P14 is unreasonable, which requires La to bind with three different PO4 groups. The last three fits are fits with increasing paths, in which CN was fitted, the fitted parameters are reasonable, EXCEPT for the negative ss parameters for the path La-P11 (edge sharing) and La-P14 (corner sharing). By the way, the length for La-P14 is +0.3 A, it is large, but not completely unreasonable, because the bond distances of La-O polyhedron may change from 2.4 to 3.1 A. Is it possible to constrain ss parameter? If so, how to set up this constrain? Thank you so much for your further instruction. Dien -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Wednesday, September 14, 2022 4:03 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: Larch: Fitting error of the objective/model function (Matt Newville) 2. Re: Help for EXAFS fitting (Matt Newville) ---------------------------------------------------------------------- Message: 1 Date: Wed, 14 Sep 2022 13:28:38 -0500 From: Matt Newville <newville(a)cars.uchicago.edu> To: XAFS Analysis using Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] Larch: Fitting error of the objective/model function Message-ID: <CA+7ESbodGVSNHuzTHZoeb3iL-jUsWFpeYM7TqLQPkkSyMyE2DA(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hi Fan, Sorry for the trouble. That seems like a strange error to me - I don't see why changing those expressions for E0s (even if they are "slightly complicated"!) should generate NaNs or Infinities. I don't think I've seen that happen with "feffit" fittings. Can you send me a Larch Session File with this fit in it? One suggestion is to place bounds (say +/- 20 eV) on those Parameters, say pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr', min=-20, max=20) But I'm not certain whether that would solve this problem. On Wed, Sep 14, 2022 at 7:53 AM <dxfan(a)post.kek.jp> wrote: > Dear All > > > > I am doing Temperature-dependent EXAFS experiment with a lot of data. > > > > Usually, we do these kinds of data fitting by several steps, like below: > > First, put every parameter free, and obtain the averaged value of amp. > > Second, set the amp to the averaged value, put other parameters free, and > then obtain the averaged value of del_e0. > > Third, set the amp and del_e0 to the averaged value, and fit again. > > > > In my case, my sample is perovskite structure (Ti K-edge of SrTiO3). > > To increase the fitting accuracy, I use three del_e0 for O, Ti, Sr as > suggested in paper: Haskel, D., et al. Physica B: Condensed Matter 208 > (1995): 151-153. > > The fitting parameters of Cubic model is this: > > setattr(pars, f'alpha', param(0, vary=True)) > > setattr(pars, f'amp', param(0, vary=True)) > > setattr(pars, f'del_e0_O', param(0, vary=True)) > > setattr(pars, f'del_e0_Sr', param(0, vary=True)) > > setattr(pars, f'del_e0_Ti', param(0, vary=True)) > > setattr(pars, f'sig2_O', param(.002, vary=True)) > > setattr(pars, f'sig2_Sr', param(.002, vary=True)) > > setattr(pars, f'sig2_Ti', param(.002, vary=True)) > > setattr(pars, f'sig2_Tr1', param(.002, vary=True)) > > setattr(pars, f'sig2_p', param(.002, vary=True)) > > setattr(pars, f'sig2_Tr2', param(.002, vary=True)) > > > > #del_e0 for each path > > pars.del_e0_1=param(expr='del_e0_O') > > pars.del_e0_2=param(expr='del_e0_O') > > pars.del_e0_3=param(expr='del_e0_Sr') > > pars.del_e0_4=param(expr='del_e0_Ti') > > pars.del_e0_5=param(expr='del_e0_O') > > pars.del_e0_6=param(expr='0.5*del_e0_O+0.5*del_e0_Ti') > > pars.del_e0_7=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_8=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_9=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_10=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr') > > > > In the first step, the fitting is fine, I obtained the averaged amp. > > However, in the second step, when I set amp to the averaged value, Error > happens for ?some? of the data. > > When I use different averaged amp value, the data that happens error is > different. > > The error is: > > Traceback (most recent call last): > > File "STO16_C_2.py", line 250, in <module> > > out = feffit(pars, dset) > > File > "D:\anaconda3\envs\xraylarch\lib\site-packages\larch\xafs\feffit.py", line > 557, in feffit > > result = fit.leastsq() > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 1689, in leastsq > > lsout = scipy_leastsq(self.__residual, variables, **lskws) > > File > "D:\anaconda3\envs\xraylarch\lib\site-packages\scipy\optimize\minpack.py", > line 423, in leastsq > > retval = _minpack._lmdif(func, x0, args, full_output, ftol, xtol, > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 601, in __residual > > return _nan_policy(np.asarray(out).ravel(), > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 2436, in _nan_policy > > raise ValueError(msg) > > ValueError: NaN values detected in your input data or the output of your > objective/model function - fitting algorithms cannot handle this! Please > read > https://lmfit.github.io/lmfit-py/faq.html#i-get-errors-from-nan-in-my-fit-w… > for more information. > > > > I don?t know what happened, can somebody help me figure this out? > > > > PS: when I use only one del_e0 for every path, no such error happens. > > > > Best regards > > Fan > _______________________________________________ > Ifeffit mailing list > Ifeffit(a)millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit > -- --Matt Newville <newville at cars.uchicago.edu> 630-327-7411

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Re: [Ifeffit] [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10
by Dien.Li＠srnl.doe.gov 15 Sep '22

15 Sep '22

Hi, Matt and EXAFS experts Thank you so much. Our sample is porous silica + PO4 ligand on surface/pore, then react with LaNO3 in solution. The model is that La is bonding with PO4 through both mono- (corner-sharing) and di-dentate (edge sharing) modes. Please see the attachment. The first three fits in history are fits with increasing paths, with fixed CN for the La-P11 and La-P14 path, the ss parameters are reasonable, but to fix CN at 3 for La-P14 is unreasonable, which requires La to bind with three different PO4 groups. The last three fits are fits with increasing paths, in which CN was fitted, the fitted parameters are reasonable, EXCEPT for the negative ss parameters for the path La-P11 (edge sharing) and La-P14 (corner sharing). By the way, the length for La-P14 is +0.3 A, it is large, but not completely unreasonable, because the bond distances of La-O polyhedron may change from 2.4 to 3.1 A. Is it possible to constrain ss parameter? If so, how to set up this constrain? Thank you so much for your further instruction. Dien -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Wednesday, September 14, 2022 4:03 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 10 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Re: Larch: Fitting error of the objective/model function (Matt Newville) 2. Re: Help for EXAFS fitting (Matt Newville) ---------------------------------------------------------------------- Message: 1 Date: Wed, 14 Sep 2022 13:28:38 -0500 From: Matt Newville <newville(a)cars.uchicago.edu> To: XAFS Analysis using Ifeffit <ifeffit(a)millenia.cars.aps.anl.gov> Subject: Re: [Ifeffit] Larch: Fitting error of the objective/model function Message-ID: <CA+7ESbodGVSNHuzTHZoeb3iL-jUsWFpeYM7TqLQPkkSyMyE2DA(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hi Fan, Sorry for the trouble. That seems like a strange error to me - I don't see why changing those expressions for E0s (even if they are "slightly complicated"!) should generate NaNs or Infinities. I don't think I've seen that happen with "feffit" fittings. Can you send me a Larch Session File with this fit in it? One suggestion is to place bounds (say +/- 20 eV) on those Parameters, say pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr', min=-20, max=20) But I'm not certain whether that would solve this problem. On Wed, Sep 14, 2022 at 7:53 AM <dxfan(a)post.kek.jp> wrote: > Dear All > > > > I am doing Temperature-dependent EXAFS experiment with a lot of data. > > > > Usually, we do these kinds of data fitting by several steps, like below: > > First, put every parameter free, and obtain the averaged value of amp. > > Second, set the amp to the averaged value, put other parameters free, and > then obtain the averaged value of del_e0. > > Third, set the amp and del_e0 to the averaged value, and fit again. > > > > In my case, my sample is perovskite structure (Ti K-edge of SrTiO3). > > To increase the fitting accuracy, I use three del_e0 for O, Ti, Sr as > suggested in paper: Haskel, D., et al. Physica B: Condensed Matter 208 > (1995): 151-153. > > The fitting parameters of Cubic model is this: > > setattr(pars, f'alpha', param(0, vary=True)) > > setattr(pars, f'amp', param(0, vary=True)) > > setattr(pars, f'del_e0_O', param(0, vary=True)) > > setattr(pars, f'del_e0_Sr', param(0, vary=True)) > > setattr(pars, f'del_e0_Ti', param(0, vary=True)) > > setattr(pars, f'sig2_O', param(.002, vary=True)) > > setattr(pars, f'sig2_Sr', param(.002, vary=True)) > > setattr(pars, f'sig2_Ti', param(.002, vary=True)) > > setattr(pars, f'sig2_Tr1', param(.002, vary=True)) > > setattr(pars, f'sig2_p', param(.002, vary=True)) > > setattr(pars, f'sig2_Tr2', param(.002, vary=True)) > > > > #del_e0 for each path > > pars.del_e0_1=param(expr='del_e0_O') > > pars.del_e0_2=param(expr='del_e0_O') > > pars.del_e0_3=param(expr='del_e0_Sr') > > pars.del_e0_4=param(expr='del_e0_Ti') > > pars.del_e0_5=param(expr='del_e0_O') > > pars.del_e0_6=param(expr='0.5*del_e0_O+0.5*del_e0_Ti') > > pars.del_e0_7=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_8=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_9=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_10=param(expr='(2*del_e0_O+del_e0_Ti)/3') > > pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr') > > > > In the first step, the fitting is fine, I obtained the averaged amp. > > However, in the second step, when I set amp to the averaged value, Error > happens for ?some? of the data. > > When I use different averaged amp value, the data that happens error is > different. > > The error is: > > Traceback (most recent call last): > > File "STO16_C_2.py", line 250, in <module> > > out = feffit(pars, dset) > > File > "D:\anaconda3\envs\xraylarch\lib\site-packages\larch\xafs\feffit.py", line > 557, in feffit > > result = fit.leastsq() > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 1689, in leastsq > > lsout = scipy_leastsq(self.__residual, variables, **lskws) > > File > "D:\anaconda3\envs\xraylarch\lib\site-packages\scipy\optimize\minpack.py", > line 423, in leastsq > > retval = _minpack._lmdif(func, x0, args, full_output, ftol, xtol, > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 601, in __residual > > return _nan_policy(np.asarray(out).ravel(), > > File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", > line 2436, in _nan_policy > > raise ValueError(msg) > > ValueError: NaN values detected in your input data or the output of your > objective/model function - fitting algorithms cannot handle this! Please > read > https://lmfit.github.io/lmfit-py/faq.html#i-get-errors-from-nan-in-my-fit-w… > for more information. > > > > I don?t know what happened, can somebody help me figure this out? > > > > PS: when I use only one del_e0 for every path, no such error happens. > > > > Best regards > > Fan > _______________________________________________ > Ifeffit mailing list > Ifeffit(a)millenia.cars.aps.anl.gov > http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit > Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit > -- --Matt Newville <newville at cars.uchicago.edu> 630-327-7411

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Help for EXAFS fitting
by Dien.Li＠srnl.doe.gov 14 Sep '22

14 Sep '22

Hi, Matt and Carlo and other EXAFS experts Attached please find a fpj data file. The basic system is silica + PO4 ligand on surfaces, which was used for adsorption of La. We collected La L3-edge EAXFS data and did this fitting. I used two models of La binding as monodentate and bidentate. I saw the negative ss parameter. I saw this in some of my other EXAFS data fitting samples as well. I have two questions for help: 1. What might cause the negative ss parameters and how I may improve this, is this caused by incorrect structure models 2. If we can do some "stress" test to make sure the fitting is valid and meaningful. Please you can help look at and play this data set and direct me on how to do this correctly, thank you so much. Dien Li Savannah River National Laboratory

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Larch: Fitting error of the objective/model function
by dxfan＠post.kek.jp 14 Sep '22

14 Sep '22

Dear All I am doing Temperature-dependent EXAFS experiment with a lot of data. Usually, we do these kinds of data fitting by several steps, like below: First, put every parameter free, and obtain the averaged value of amp. Second, set the amp to the averaged value, put other parameters free, and then obtain the averaged value of del_e0. Third, set the amp and del_e0 to the averaged value, and fit again. In my case, my sample is perovskite structure (Ti K-edge of SrTiO3). To increase the fitting accuracy, I use three del_e0 for O, Ti, Sr as suggested in paper: Haskel, D., et al. Physica B: Condensed Matter 208 (1995): 151-153. The fitting parameters of Cubic model is this: setattr(pars, f'alpha', param(0, vary=True)) setattr(pars, f'amp', param(0, vary=True)) setattr(pars, f'del_e0_O', param(0, vary=True)) setattr(pars, f'del_e0_Sr', param(0, vary=True)) setattr(pars, f'del_e0_Ti', param(0, vary=True)) setattr(pars, f'sig2_O', param(.002, vary=True)) setattr(pars, f'sig2_Sr', param(.002, vary=True)) setattr(pars, f'sig2_Ti', param(.002, vary=True)) setattr(pars, f'sig2_Tr1', param(.002, vary=True)) setattr(pars, f'sig2_p', param(.002, vary=True)) setattr(pars, f'sig2_Tr2', param(.002, vary=True)) #del_e0 for each path pars.del_e0_1=param(expr='del_e0_O') pars.del_e0_2=param(expr='del_e0_O') pars.del_e0_3=param(expr='del_e0_Sr') pars.del_e0_4=param(expr='del_e0_Ti') pars.del_e0_5=param(expr='del_e0_O') pars.del_e0_6=param(expr='0.5*del_e0_O+0.5*del_e0_Ti') pars.del_e0_7=param(expr='(2*del_e0_O+del_e0_Ti)/3') pars.del_e0_8=param(expr='(2*del_e0_O+del_e0_Ti)/3') pars.del_e0_9=param(expr='(2*del_e0_O+del_e0_Ti)/3') pars.del_e0_10=param(expr='(2*del_e0_O+del_e0_Ti)/3') pars.del_e0_11=param(expr='0.5*del_e0_O+0.5*del_e0_Sr') In the first step, the fitting is fine, I obtained the averaged amp. However, in the second step, when I set amp to the averaged value, Error happens for "some" of the data. When I use different averaged amp value, the data that happens error is different. The error is: Traceback (most recent call last): File "STO16_C_2.py", line 250, in <module> out = feffit(pars, dset) File "D:\anaconda3\envs\xraylarch\lib\site-packages\larch\xafs\feffit.py", line 557, in feffit result = fit.leastsq() File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", line 1689, in leastsq lsout = scipy_leastsq(self.__residual, variables, **lskws) File "D:\anaconda3\envs\xraylarch\lib\site-packages\scipy\optimize\minpack.py", line 423, in leastsq retval = _minpack._lmdif(func, x0, args, full_output, ftol, xtol, File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", line 601, in __residual return _nan_policy(np.asarray(out).ravel(), File "D:\anaconda3\envs\xraylarch\lib\site-packages\lmfit\minimizer.py", line 2436, in _nan_policy raise ValueError(msg) ValueError: NaN values detected in your input data or the output of your objective/model function - fitting algorithms cannot handle this! Please read https://lmfit.github.io/lmfit-py/faq.html#i-get-errors-from-nan-in-my-fit-wh at-can-i-do for more information. I don't know what happened, can somebody help me figure this out? PS: when I use only one del_e0 for every path, no such error happens. Best regards Fan

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FW: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 3
by Dien.Li＠srnl.doe.gov 13 Sep '22

13 Sep '22

Hi Matt and all I sent this and an attachment before. I hope you can help figure out why I often get negative ss parameter from fitting? For this specific example, if I fit the CN, it yields CN of ~1, the monodendate structure is reasonable, but I got negative ss. However, if I fixed CN at 3, the ss is reasonable, but it needs to bind with three different PO4 on the surfaces, this is interesting but I am uncertain. Thank you so much for your any advice. Dien Li Savannah River National Laboratory -----Original Message----- From: Ifeffit <ifeffit-bounces(a)millenia.cars.aps.anl.gov> On Behalf Of ifeffit-request(a)millenia.cars.aps.anl.gov Sent: Friday, September 9, 2022 12:32 PM To: ifeffit(a)millenia.cars.aps.anl.gov Subject: [EXTERNAL] Ifeffit Digest, Vol 235, Issue 3 Send Ifeffit mailing list submissions to ifeffit(a)millenia.cars.aps.anl.gov To subscribe or unsubscribe via the World Wide Web, visit http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit or, via email, send a message with subject or body 'help' to ifeffit-request(a)millenia.cars.aps.anl.gov You can reach the person managing the list at ifeffit-owner(a)millenia.cars.aps.anl.gov When replying, please edit your Subject line so it is more specific than "Re: Contents of Ifeffit digest..." Today's Topics: 1. Help for EXAFS fitting (Dien.Li(a)srnl.doe.gov) ---------------------------------------------------------------------- Message: 1 Date: Fri, 9 Sep 2022 16:31:38 +0000 From: "Dien.Li(a)srnl.doe.gov" <Dien.Li(a)srnl.doe.gov> To: "ifeffit(a)millenia.cars.aps.anl.gov" <ifeffit(a)millenia.cars.aps.anl.gov> Subject: [Ifeffit] Help for EXAFS fitting Message-ID: <DM8PR09MB62323624C91F0A43DC7CB6D1C4439(a)DM8PR09MB6232.namprd09.prod.outlook.com> Content-Type: text/plain; charset="us-ascii" Hi, Matt and Carlo and other EXAFS experts Attached please find a fpj data file. The basic system is silica + PO4 ligand on surfaces, which was used for adsorption of La. We collected La L3-edge EAXFS data and did this fitting. I used two models of La binding as monodentate and bidentate. I saw the negative ss parameter. I saw this in some of my other EXAFS data fitting samples as well. I have two questions for help: 1. What might cause the negative ss parameters and how I may improve this, is this caused by incorrect structure models 2. If we can do some "stress" test to make sure the fitting is valid and meaningful. Please you can help look at and play this data set and direct me on how to do this correctly, thank you so much. Dien Li Savannah River National Laboratory

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Fitting multiple spectra simultaneously with Larch
by Van Stappen, Casey M 12 Sep '22

12 Sep '22

Dear Ifeffit team, I’d like to fit multiple EXAFS spectra simultaneously in Larch using several common parameters/relative restraints, but have not found a way to do so (yet). I’ve gone through Dr. Matt Newville’s youtube tutorials (generally very helpful), but this topic doesn’t seem to have been covered. Any suggestions? Thanks! Best, Casey Van Stappen ------------------------------------------------------------------------ Dr. Casey Van Stappen University of Texas at Austin Robert A. Welch Hall, 4.318 2350 Speedway Austin, TX 78705 USA Phone: +1 (512) 775-2658 E-mail: casey.vanstappen(a)austin.utexas.edu

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Icon Resolution issue in 14 inch
by Mohamad Numan 12 Sep '22

12 Sep '22

Dear Developers, I am using the Demeter package on my windows 11 laptop. I am facing some resolution issues in the icons of Athena and Artemis. The icons look pretty dull and very distressing to the eyes. Attaching a screenshot for your reference. I will be happy to hear an update from you. Thanks & Regards Mohamad Numan Ph.D. Student, IACS

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Virtual SSRL Summer School on Synchrotron X-Ray Absorption Spectroscopy and Imaging Oct 25-28, 2022
by Ritimukta Sarangi 06 Sep '22

06 Sep '22

Hello EXAFS enthusiasts, We are hosting the SSRL "not quite summer" summer school at the end of October this year (Oct 25-28). We wanted to include real experiments and deferred the school to the start of operations at SSRL. The event is virtual and all information (including registration details) can be found at: https://conf.slac.stanford.edu/exafs-2022/ We recognize that there are several really good online resources for learning about EXAFS and it has proved to be quite beneficial to the new and experienced learners alike. We have changed our summer school format to include additional teaching modules that can help participants learn aspects of EXAFS data analysis that are beyond what we have typically taught in the past. These new modules are especially helpful to the novice user and include: 1) Opportunity to write a 1 to 1.5 page proposal to compete for experimental time during the school. 2) A complete 1-day remote data measurement and hands-on demonstration of beamline optimization and experiment setup during the live session. 3) Insights into becoming a user at SSRL, proposal writing and its review process with examples of past successful proposals. Looking forward to seeing some of you at the school. Best Regards, Riti Sarangi

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XAFS fitting in xas_viewer and reset of customized variables after save & load cycle
by juejing.liu＠gmail.com 04 Sep '22

04 Sep '22

Hi all, I am using xas_viewer, version 0.9.65, to fit some XAFS data. In a typical situation I will also fit the coordination numbers of atoms by add customized variables in the amplitude boxes (image below). It works fine during my fitting. However, when I save my result as a larch session and load it later, all my customized parameters are disappeared, and the amplitude boxes are reset. Therefore, I need to refill all the variables after each save & load cycle. This becomes increasingly tedious when dealing with about 20 different paths. Is there any workaround of this problem? Best, Juejing Liu Guo Group Materials Science and Engineering program Alexandra Navrotsky Institute for Experimental Thermodynamics Washington State University Pullman, WA 99164-4630 Office: Fulmer Hall, Room 630 Phone: 208-206-7304

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Simultaneous multispectral fitting in Larch?
by Van Stappen, Casey M 30 Aug '22

30 Aug '22

To whom it concerns, I wanted to inquire regarding how best to perform multispectral fitting (i.e. fitting several EXAFS spectra simultaneously with shared parameters) in Larch? This was something that could be done with (relative) ease in Artemis, but I was hoping to perform this at a larger scale (6 spectra, >10 restrictions) in Larch. I’ve hunted through Dr. Newville’s excellent Youtube tutorials, but didn’t find this specific information. Thank you for your help! Best, Casey Van Stappen ------------------------------------------------------------------------ Dr. Casey Van Stappen University of Texas at Austin Robert A. Welch Hall, 4.318 2350 Speedway Austin, TX 78705 USA Phone: +1 (512) 775-2658 E-mail: casey.vanstappen(a)austin.utexas.edu

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XAFS short course at BNL: November 2-4
by Anatoly Frenkel 29 Aug '22

29 Aug '22

Dear subscribers, This is a reminder about the annual XAFS short course at BNL. The dates are: November 2-4. It will be virtual. The level will be intermediate to advanced As in the past, lectures, discussions and software demonstration sessions will be on Wednesday and Thursday, and the full day data analysis practicum will be on Friday. The course agenda and the link to the application form are available at the BNL web site: https://www.bnl.gov/xafscourse/index.php and at the web site of the Synchrotron Catalysis Consortium: https://you.stonybrook.edu/scc2/xafs-workshops/ Registration deadline is September 11. Regards, Anatoly ------------------------------------------------------------------- Anatoly I. Frenkel Professor Department of Materials Science and Chemical Engineering Stony Brook University Stony Brook, NY 11794 Email: anatoly.frenkel(a)stonybrook.edu <https://mail.bnl.gov/OWA/redir.aspx?C=F6wCGt4adziN6IvpdRQ-rWdgy3Oaoif_x-0yb…> http://you.stonybrook.edu/frenkel Co-Director and Spokesperson, Synchrotron Catalysis Consortium (SCC) at BNL http://you.stonybrook.edu/scc2 Joint Appointment: Senior Chemist Chemistry Division, Brookhaven National Laboratory Upton, NY 11973. Ph: 631-344-3013. Group: 631-344-3494 Email: frenkel(a)bnl.gov https://www.bnl.gov/staff/frenkel -------------------------------------------------------------------

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Question related to an example of EXAFS fitting using Larch
by Andy Zhang 29 Aug '22

29 Aug '22

Dear all, I am learning Larch and read the manual of Larch online. In the "13.8.10. Example 3: Fit 3 datasets with 1 Path" of the webpage https://xraypy.github.io/xraylarch/xafs_feffit.html#example-3-fit-3-dataset…, it shows an example that fitting Cu at different temperatures. Einstein model was used to simulate the sigma2, as shown in the figure below. [image: image.png] However, in some papers (eg. Radiation Physicsand Chemistry137 (2017) 93–98) that model EXAFS at elevated temperatures, they separates the total sigma2 to static and thermo components (Sigma^2 = Sigma_static^2 + Sigma_thermo^2), which is different from the above Larch example. I am a little confused about the utilization of Einstein model. I wonder if the Sigma2 obtained by Einstein model can reflect the total sigma2 or can only reflect the thermo part. Many thanks for your help! Best regards, Harry

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Re: [Ifeffit] XAFS fitting in xas_viewer and reset of customized
by juejing.liu＠gmail.com 28 Aug '22

28 Aug '22

Hi Matt, Here is the session file for the UO2 fitting. The screenshot blow shows what the customized variables look like right before saving this session. Please feel free to let me know if you need any extra information. Best, Juejing Liu Guo Group Materials Science and Engineering program Alexandra Navrotsky Institute for Experimental Thermodynamics Washington State University Pullman, WA 99164-4630 Office: Fulmer Hall, Room 630 Phone: 208-206-7304

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Re: [Ifeffit] XAFS fitting in xas_viewer and reset of customized variables after save & load cycle
by Liu, Juejing 28 Aug '22

28 Aug '22

Hi Matt, Thanks for the quick response. I just noticed that the data in the screenshot is unpublished data so I may not be able to send you that one. But I will send you a typical UO2 fitting later today (in the larch session) so that you can look. Best, Juejing Liu Guo Group Materials Science and Engineering program Alexandra Navrotsky Institute for Experimental Thermodynamics Washington State University Pullman, WA 99164-4630 Office: Fulmer Hall, Room 630 Phone: 208-206-7304

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Quick Absorption and Scattering (QAS) beamline scientist position at NSLS II
by Stavitski, Eli 26 Aug '22

26 Aug '22

Dear all, We are looking for a beamline scientist for Quick Absorption and Scattering (QAS) beamline (https://www.bnl.gov/nsls2/beamlines/beamline.php?r=7-BM) The full job description is available here https://jobs.bnl.gov/job/upton/beamline-scientist-quick-x-ray-absorption-an… ____________________________________ Eli Stavitski, PhD, Physicist Inner Shell Spectroscopy (ISS) Lead Beamline Scientist National Synchrotron Light Source-II Bldg. 743, Brookhaven National Laboratory Upton, NY 11973-5000 631 344 8641 istavitski(a)bnl.gov<mailto:istavitski@bnl.gov> https://www.bnl.gov/ps/beamlines/beamline.php?r=8-ID

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third cumulant in Larch
by Andy Zhang 19 Aug '22

19 Aug '22

Dear all, I have a quick question related to EXAFS fitting using Larch. I wonder how to include the third cumulant in the fitting. I tried to add "third" in the "pars" section, but it seems it did not work. [image: image.png] Thanks a lot for your help! Have a nice day! Best, Harry

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Environmental geochemist position at DOE-National Energy Technology Laboratory
by Mengling Stuckman 18 Aug '22

18 Aug '22

Dear ifeffit members, Recently we are interested in hiring an environmental geochemist for our critical mineral sustainability program at NETL, Pittsburgh, PA. Synchrotron experience is a plus. U.S. citizens are strongly preferred. Here is the specific job posting. https://leidos.wd5.myworkdayjobs.com/External/job/Pittsburgh-PA/Environment… Feel free to pass along this information to your students who are interested. If you have any questions related to the post, feel free to contact me at mengling.stuckman(a)netl.doe.gov Thanks and have a nice day, Mengling -- Mengling Stuckman Leidos Technical Fellow National Energy Technology Laboratory U.S. Department of Energy Pittsburgh, PA mengling.stuckman(a)netl.doe.gov Office: 412-386-7387

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Using larch for feff Fitting -> simple 4 parameter fit
by Mangold, Stefan (IPS) 18 Aug '22

18 Aug '22

Dear all, I try to use larch for Feff Fitting. For a first start, I liked the option of Artemis with the „simple 4 parameter fit“. Larch produces for every path an independent dear and sigma2. Is there a simple way to make this simple 4 parameter fit also in larch? best regards Stefan Mangold

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XAFS short course at BNL: November 2-4
by Anatoly Frenkel 09 Aug '22

09 Aug '22

Dear subscribers: Please spread the word to those who may be interested in our next annual short course at BNL on X-ray absorption fine structure. The dates are: November 2-4. It will be virtual. The level will be intermediate to advance (last year it was a beginner level). As in the past, lectures, discussions and software demonstration sessions will be on Wednesday and Thursday, and the full day data analysis practicum will be on Friday. More information about the course and the link to the application form will appear soon on BNL web site, and on the web site of the Synchrotron Catalysis Consortium (SCC). Regards, Anatoly ------------------------------------------------------------------- Anatoly I. Frenkel Professor Department of Materials Science and Chemical Engineering Stony Brook University Stony Brook, NY 11794 Email: anatoly.frenkel(a)stonybrook.edu <https://mail.bnl.gov/OWA/redir.aspx?C=F6wCGt4adziN6IvpdRQ-rWdgy3Oaoif_x-0yb…> http://you.stonybrook.edu/frenkel Co-Director and Spokesperson, Synchrotron Catalysis Consortium (SCC) at BNL http://you.stonybrook.edu/scc2 Joint Appointment: Senior Chemist Chemistry Division, Brookhaven National Laboratory Upton, NY 11973. Ph: 631-344-3013. Group: 631-344-3494 Email: frenkel(a)bnl.gov https://www.bnl.gov/staff/frenkel -------------------------------------------------------------------

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