[Ifeffit] Calculation of metal concentration (and hence density) from Edge Jump

Mon Feb 27 01:03:11 CST 2017

Dear Alexey,
   Yes it certainly helped. I was almost on the correct lines but was not
completely aware of the ion chamber consideration. I will check the values
for amplification and will take the proper values into the consideration.
Sincerely yours
Pushkar

On Mon, Feb 27, 2017 at 3:53 PM, Alexey Boubnov <alexeyboubnov at gmail.com>
wrote:

> Dear Pushkar,
>
> 1) µ is the total absorption at a given energy. If you are above the edge,
> it will be higher than if you are below. Test it by changing the energy.
> NOTE that the absorption value you have in Athena is calculated form the
> ion chamber values, which are amplified. If I2 is amplified 10x higher than
> I1, -log(I2/I1) will be -log(10) = -1, i.e. lower by 1 relative to the real
> value. Knowing the amplification factors, you can take this into account.
> 2) yes. Athena determines it for you during normalisation. It is the
> difference between the pre-edge and post-edge fit curves at the position of
> E0. This is the proper way of determining the edge step.
> 3) yes. This is a statistical thing. Try to normalise using different
> ranges and you will get slightly different values of Delta µ. The standard
> deviation you can give as delta µ. If the uncertainty does not interest
> you, you can probably set this value to 0.
>
> Hope this helps.
> Alexey
>
>
> 2017-02-27 5:56 GMT+01:00 pushkar shejwalkar <pshejwalkar2004 at gmail.com>:
>
>> Dear Alexey,
>>       Thank you for your insightful suggestions and very useful
>> information. Now that I have got the XAFSmass program running (?) it is
>> giving me some values and no more error. So I am assuming that I am doing
>> everything right. However, I still have some questions regarding the
>> READING and UNDERSTANDING of the data input and output from the program.
>> From the manual, it is not very clear and difficult to understand some of
>> the input values. In the unknown concentration tab
>> 1) u = high u?? meaning highest absorption?
>> 2) DELTA ud is = to deltaU i.e. typically what we get as edge step in
>> Athena??
>> 3) deltaut = uncertainty?
>> For the novice learner like me could you please tell me how exactly can
>> we calculate these values from the single spectra (preferably). I am aware
>> of the crude ways to find it but would like to more proper and scientific
>> way.
>> By the Way, in order to establish these values, should we use the crude
>> data file or properly processed data file e.g. K-weight corrected,
>> background adjusted, aligned and calibrated data?
>> Sorry for the inconvenience and thank you very much in advance for the
>> details.
>> Sincerely yours
>> Pushkar
>>
>> On Thu, Feb 23, 2017 at 6:18 PM, Alexey Boubnov <alexeyboubnov at gmail.com>
>> wrote:
>>
>>> Dear Pushkar,
>>>
>>> 1) M%x is the mass percentage.
>>> 2) This function is for calculating the element concentration from the
>>> absorption spectrum. XAFSmass does not have problems with long formulas.
>>> You wrote the formula correctly, but maybe you did not indicate also the
>>> total absorption, edge jump with uncertainty and energy?
>>>
>>> All the best.
>>> Alexey
>>>
>>> 2017-02-23 2:54 GMT+01:00 pushkar shejwalkar <pshejwalkar2004 at gmail.com>
>>> :
>>>
>>>> Thank you, Alexey, for very useful information. Currently, I am working
>>>> on XAFSmass. Technically it looks much more flexible than the software
>>>> provided by SPring-8 since almost all the variables can be changed and
>>>> adjusted as per the requirements.
>>>> 1) However, sample information is very tedious to put in and confusing
>>>> as well. Do you happen to know what exactly does M%x (is this mass % or
>>>> mole %).
>>>> 2) I am working on the tab with the determination of unknown
>>>> concentration Label and I am interested in finding out the Fe concentration
>>>> only. So I should write Fe%x (I assume). However, since I use
>>>> organosilica's the formula is not so straightforward. My empirical formula
>>>> for the catalyst is FeC580H382O152Si98N10F6S2. Do you think the program can
>>>> handle such information? I wrote Fe%xC_580H_382O_152Si_98N_10F_6S_2.
>>>> But it is giving an error that 'can not calculate concentration'. Am I
>>>> doing something wrong?
>>>> I have already read the pdf in the software and as such it looks not so
>>>> complicated but just the syntax of writing chemical formula is different
>>>> and con-conventional.
>>>>
>>>> Sincerely yours
>>>> Pushkar
>>>>
>>>> On Wed, Feb 22, 2017 at 9:52 PM, Alexey Boubnov <
>>>> alexeyboubnov at gmail.com> wrote:
>>>>
>>>>> Dear Pushkar,
>>>>>
>>>>> regarding your last question: the absorption edge jump (Delta µd) is
>>>>> the difference in absorption before the edge and after the edge, e.g. Pt
>>>>> L3-edge is at 11564 eV, so Delta(µd) = µd at 11580 eV - µd at 11550 eV. The
>>>>> total absorption (µd) takes all atoms into account. You only need the
>>>>> difference. I and I0 do not contain information on the sample, so they are
>>>>> useless for this purpose.
>>>>>
>>>>> Regarding your original question (calculation of the edge jump knowing
>>>>> the composition of your sample): there are programs available to calculate
>>>>> the edge jump and amount of sample from the composition and total
>>>>> absorption, saving you the effort with formulas and letting you focus on
>>>>> your sample. Try XAFSmass (https://intranet.cells.es/Bea
>>>>> mlines/CLAESS/software/xafsmass.html).
>>>>>
>>>>> Here you can enter the bulk composition (e.g. Fe%10SiO_2 for a
>>>>> silicate with 10% Fe-content), energy (e.g. slightly above Fe K-edge: 7150
>>>>> eV), pellet area (e.g. 1.3 cm²), total absorption (e.g. µd = 1) and press
>>>>> "calculate". This gives you the mass of your sample (e.g. 12 mg
>>>>> [hypothetical value]) and the edge jump due to the Fe K-edge (e.g.
>>>>> Delta(µd) = 0.2 [hypothetical value]). The mass and edge jump are
>>>>> approximately proportional. Consequently if your pellet in reality contains
>>>>> 60 mg iron silicate (5x the calculated number), absorption values will also
>>>>> scale: Delta(µd) = 1.0 and µd = 5, which is a little too high. Play around
>>>>> with the value of µd in the program to see the effect on mass and edge jump.
>>>>>
>>>>> I wish you successful calculations and experiments!
>>>>> Alexey
>>>>>
>>>>> 2017-02-22 5:54 GMT+01:00 pushkar shejwalkar <
>>>>> pshejwalkar2004 at gmail.com>:
>>>>>
>>>>>> Thank you, Bruce and Alexey for your kind information.
>>>>>> Bruce the communication, unfortunately, is not available on our
>>>>>> Internet connection from university to download for free. Do you think it
>>>>>> would be possible (under the copyrights act off course) for you send a PDF
>>>>>> copy? The communication seems really interesting and I will keep the
>>>>>> procedure in mind (for March Dates when we have BL for us again) to make
>>>>>> sure that we have a calibration curve. (off course XRF is more reliable and
>>>>>> easy).
>>>>>> Alexey, I read the section (also some other information in that
>>>>>> book). The book is really great. Thanks for sharing.
>>>>>> I have already sat down with the pen and paper. but just want to know
>>>>>> one thing. Is Edge Jump = Absorbance?? or we need to calculate the
>>>>>> absorbance by actually practically finding out the I and Io?
>>>>>> e.g. if edge jump = absorbance I can modify the equation I = Io^e-upd
>>>>>> into its A form. If not I will use ion chamber gas ratio to calculate the I
>>>>>> and Io respectively.
>>>>>> Which way is more correct?
>>>>>> Best Regards
>>>>>> Pushkar
>>>>>>
>>>>>> On Tue, Feb 21, 2017 at 10:15 PM, Bruce Ravel <bravel at bnl.gov> wrote:
>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> This might help: https://doi.org/10.1107/S1600577514001283
>>>>>>>
>>>>>>> Note that we measured a sequence of standards of known thickness and
>>>>>>> concentration /prior/ to the rest of the experiment, so the methodology in
>>>>>>> that paper might not be useful after the fact in the absence of that prep
>>>>>>> work.
>>>>>>>
>>>>>>> B
>>>>>>>
>>>>>>>
>>>>>>> On 02/20/2017 10:19 PM, pushkar shejwalkar wrote:
>>>>>>>
>>>>>>>> Dear All,
>>>>>>>>     First of all, is it possible to calculate the concentration of
>>>>>>>> metal
>>>>>>>> (loading, therefore) from just the edge jump? Is there a simpler
>>>>>>>> equation like knowing the Flux values or some basic instrumental
>>>>>>>> information we can calculate the concentration term using Io and It
>>>>>>>> values of beamline (the simplest form of Beer-lambert law)? if so
>>>>>>>> what
>>>>>>>> formula should we use.
>>>>>>>> I searched in the mailing list archive and have found one such
>>>>>>>> archive
>>>>>>>> but it discusses how to use calculation to find out how much sample
>>>>>>>> would be needed to get the edge jump. I am rather interested in the
>>>>>>>> reverse way. I have an experimental edge jump and want to calculate
>>>>>>>> (if
>>>>>>>> possible with as much accuracy as possible) the concentration of
>>>>>>>> metal.
>>>>>>>> I know with only edge jump it will be difficult and XRF will be a
>>>>>>>> better
>>>>>>>> and more reliable way. But for better understanding and cross
>>>>>>>> checking
>>>>>>>> between different samples, I wish to do such calculations.
>>>>>>>> Can anyone guide me to the right direction and equations to do such
>>>>>>>> calculations?
>>>>>>>> Thank you all in advance
>>>>>>>> Warmest regards
>>>>>>>> Pushkar
>>>>>>>>
>>>>>>>> --
>>>>>>>> Best Regards,
>>>>>>>> Pushkar Shejwalkar.
>>>>>>>> Post-doctoral -Researcher,
>>>>>>>> Tokyo Engineering University,
>>>>>>>> Tokyo-to
>>>>>>>> Japan
>>>>>>>>
>>>>>>>>
>>>>>>>>
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>>>>>>>> Ifeffit at millenia.cars.aps.anl.gov
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>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>>  Bruce Ravel  ------------------------------------ bravel at bnl.gov
>>>>>>>
>>>>>>>  National Institute of Standards and Technology
>>>>>>>  Synchrotron Science Group at NSLS-II
>>>>>>>  Building 743, Room 114
>>>>>>>  Upton NY, 11973
>>>>>>>
>>>>>>>  Homepage:    http://bruceravel.github.io/home/
>>>>>>>  Software:    https://github.com/bruceravel
>>>>>>>  Demeter:     http://bruceravel.github.io/demeter/
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Ifeffit mailing list
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>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Best Regards,
>>>>>> Pushkar Shejwalkar.
>>>>>> Post-doctoral -Researcher,
>>>>>> Tokyo Engineering University,
>>>>>> Tokyo-to
>>>>>> Japan
>>>>>>
>>>>>>
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>>>>>>
>>>>>
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>>>>>
>>>>
>>>>
>>>> --
>>>> Best Regards,
>>>> Pushkar Shejwalkar.
>>>> Post-doctoral -Researcher,
>>>> Tokyo Engineering University,
>>>> Tokyo-to
>>>> Japan
>>>>
>>>>
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>>>
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>>
>>
>> --
>> Best Regards,
>> Pushkar Shejwalkar.
>> Post-doctoral -Researcher,
>> Tokyo Engineering University,
>> Tokyo-to
>> Japan
>>
>>
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>
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-- 
Best Regards,
Pushkar Shejwalkar.
Post-doctoral -Researcher,
Tokyo Engineering University,
Tokyo-to
Japan
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