Dear All This might be a stupid question, but I have not been able to track this down myself: What is the data source of the "core-hole lifetimes" (i.e. the energy widths "gamma(ch)" in eV) of the "Absorption edges" in the "Absorption" panel of Hephaestus? As far as I could see these lifetimes/widths are not given in the 'Elam database'. Other XAS data tools based on the Elam database (like e.g. 'XrayDB') claim to be using values from 'O. Keski-Rahkonen and M. O. Krause, Atomic Data and Nuclear Data Tables 14, pp139-146 (1974) (http://dx.doi.org/10.1016/S0092-640X(74)80020-3)' for this. Because that reference does not give tabulated values but rough data plots only, it is difficult to compare those with the values in Hephaestus. If someone knows the respective data source used in Hephaestus, the answer/information is deeply appreciated! Best regards Daniel
Hi, The documentation for Hephaestus lists the same paper as you indicated. (Access by going to Help-Document in Heph.) Another reference with values tabulated is: http://aip.scitation.org/doi/10.1063/1.555595 Natural widths of atomic K and L levels, Kα X‐ray lines and several KLL Auger lines Journal of Physical and Chemical Reference Data 8, 329 (1979); M. O. Krause and J. H. Oliver But I have noticed the values differ between that work and those in Heph/earlier work. Krause and Oliver did not even cite that earlier work. -R. On 11/12/2017 1:28 PM, Daniel Przyrembel wrote:
Dear All
This might be a stupid question, but I have not been able to track this down myself:
What is the data source of the "core-hole lifetimes" (i.e. the energy widths "gamma(ch)" in eV) of the "Absorption edges" in the "Absorption" panel of Hephaestus?
As far as I could see these lifetimes/widths are not given in the 'Elam database'. Other XAS data tools based on the Elam database (like e.g. 'XrayDB') claim to be using values from 'O. Keski-Rahkonen and M. O. Krause, Atomic Data and Nuclear Data Tables 14, pp139-146 (1974) (http://dx.doi.org/10.1016/S0092-640X(74)80020-3)' for this. Because that reference does not give tabulated values but rough data plots only, it is difficult to compare those with the values in Hephaestus.
If someone knows the respective data source used in Hephaestus, the answer/information is deeply appreciated!
Best regards
Daniel
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Thanks Robert! That's somehow reassuring. Still I can't see any reference to 'Keski-Rahkonen and Krause' in Hephaestus on my install (0.9.25 on Windows): Help -> Document takes me to an HTML document, "...installpath...\DemeterPerl\perl\site\lib\Demeter\share\documentation\Athena\hephaestus.html", that does not mention any reference(s) for lifetimes. Maybe that is an omission in my version of the program?! The other reference you mentioned (Krause and Oliver) I have found as well, but, alas, it only lists K and L levels and, yes, I wondered about Krause not mentioning his own work, too. In general it seems to be tedious/difficult to find core-hole lifetimes, let alone tabulated values for a broad range of elements and their core levels. That's why I am/was so keen on finding the source(s) used in Hephaestus. Especially as I would love to know whether it's experimental or theory values. In the latter case one would necessarily want to know how they were calculated in the former how they were determined... I'll keep looking around (& through the works cited by 'Krause and Oliver')... Cheers Daniel
Hi,
The documentation for Hephaestus lists the same paper as you indicated. (Access by going to Help-Document in Heph.)
Another reference with values tabulated is: http://aip.scitation.org/doi/10.1063/1.555595
Natural widths of atomic K and L levels, Kα X‐ray lines and several KLL Auger lines Journal of Physical and Chemical Reference Data 8, 329 (1979); M. O. Krause and J. H. Oliver
But I have noticed the values differ between that work and those in Heph/earlier work. Krause and Oliver did not even cite that earlier work.
-R.
On 11/12/2017 1:28 PM, Daniel Przyrembel wrote:
Dear All
This might be a stupid question, but I have not been able to track this down myself:
What is the data source of the "core-hole lifetimes" (i.e. the energy widths "gamma(ch)" in eV) of the "Absorption edges" in the "Absorption" panel of Hephaestus?
As far as I could see these lifetimes/widths are not given in the 'Elam database'. Other XAS data tools based on the Elam database (like e.g. 'XrayDB') claim to be using values from 'O. Keski-Rahkonen and M. O. Krause, Atomic Data and Nuclear Data Tables 14, pp139-146 (1974) (http://dx.doi.org/10.1016/S0092-640X(74)80020-3)' for this. Because that reference does not give tabulated values but rough data plots only, it is difficult to compare those with the values in Hephaestus.
If someone knows the respective data source used in Hephaestus, the answer/information is deeply appreciated!
Best regards
Daniel
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On 11/13/2017 11:15 AM, Daniel Przyrembel wrote:
Still I can't see any reference to 'Keski-Rahkonen and Krause' in
http://bruceravel.github.io/demeter/documents/Athena/hephaestus.html#absorpt... Here is the relevant bit from Feff: https://github.com/xraypy/feff85exafs/blob/master/src/COMMON/setgam.f Note that that bit in Feff is less sophisticated than you might think. My memory (Matt or John might remember better) is that Steve Zabinski (main author of Feff6) "interpolated" those values from the plots in the K&R paper. This was done with a ruler back in the days before we had software tools for such chores. I am not saying that the values in setgam.f are wrong -- just not as precise as you might imagine. B -- Bruce Ravel ------------------------------------ bravel@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/ Beamline: https://www.bnl.gov/ps/beamlines/beamline.php?r=6-BM Software: https://github.com/bruceravel Demeter: http://bruceravel.github.io/demeter/
Another reference that might help: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.22.1615 Core-level lifetimes as determined by x-ray photoelectron spectroscopy measurements John C. Fuggle and Santos F. Alvarado Phys. Rev. A 22, 1615 – Published 1 October 1980 X-ray photoelectron spectroscopy (XPS) has been used to measure lifetime broadening of L, M, N, O, and P core levels with binding energies less than 1500 eV in approximately 25 elements. The results show that the framework provided by previously accepted theoretical estimates of lifetime broadening is sometimes misleading. Lifetimes derived from theory and experiment often differ by a factor of 2 or more. In the transition metals of the first period plots of measured widths of the L1(2s),L2(2p12), and L3(2p32) levels as a function of atomic number show broad maxima which are not adequately described by theory. The origin of this broadening is extensively discussed, as is the overestimation of lifetimes by theory in other areas of the periodic table. Also check "Cited by" references for potentially updated information. -R. On 11/13/2017 8:34 AM, Bruce Ravel wrote:
On 11/13/2017 11:15 AM, Daniel Przyrembel wrote:
Still I can't see any reference to 'Keski-Rahkonen and Krause' in
http://bruceravel.github.io/demeter/documents/Athena/hephaestus.html#absorpt...
Here is the relevant bit from Feff:
https://github.com/xraypy/feff85exafs/blob/master/src/COMMON/setgam.f
Note that that bit in Feff is less sophisticated than you might think. My memory (Matt or John might remember better) is that Steve Zabinski (main author of Feff6) "interpolated" those values from the plots in the K&R paper. This was done with a ruler back in the days before we had software tools for such chores. I am not saying that the values in setgam.f are wrong -- just not as precise as you might imagine.
B
Hi Robert Thank you for that reference, too! Should I find a "better", more reliable set of data (I doubt it) I'll suggest it as update for Ifeffit/Athena/Hephaestus... Daniel
Another reference that might help:
https://journals.aps.org/pra/abstract/10.1103/PhysRevA.22.1615 Core-level lifetimes as determined by x-ray photoelectron spectroscopy measurements John C. Fuggle and Santos F. Alvarado Phys. Rev. A 22, 1615 – Published 1 October 1980
X-ray photoelectron spectroscopy (XPS) has been used to measure lifetime broadening of L, M, N, O, and P core levels with binding energies less than 1500 eV in approximately 25 elements. The results show that the framework provided by previously accepted theoretical estimates of lifetime broadening is sometimes misleading. Lifetimes derived from theory and experiment often differ by a factor of 2 or more. In the transition metals of the first period plots of measured widths of the L1(2s),L2(2p12), and L3(2p32) levels as a function of atomic number show broad maxima which are not adequately described by theory. The origin of this broadening is extensively discussed, as is the overestimation of lifetimes by theory in other areas of the periodic table.
Also check "Cited by" references for potentially updated information.
-R.
On 11/13/2017 8:34 AM, Bruce Ravel wrote:
On 11/13/2017 11:15 AM, Daniel Przyrembel wrote:
Still I can't see any reference to 'Keski-Rahkonen and Krause' in
http://bruceravel.github.io/demeter/documents/Athena/hephaestus.html#absorpt...
Here is the relevant bit from Feff:
https://github.com/xraypy/feff85exafs/blob/master/src/COMMON/setgam.f
Note that that bit in Feff is less sophisticated than you might think. My memory (Matt or John might remember better) is that Steve Zabinski (main author of Feff6) "interpolated" those values from the plots in the K&R paper. This was done with a ruler back in the days before we had software tools for such chores. I am not saying that the values in setgam.f are wrong -- just not as precise as you might imagine.
B
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Hi Bruce Thank you very much for your reply: It is a relief to know I have been looking in the wrong place only and that I am not blind or illiterate. I already thought that, assuming the data source was Keski-Rahkonen & Krause, the values were not precise, but accurate. And that is perfectly fine with me, I just need to know e.g. whether the natural line width of Au 4f7/2 is 0.22eV or 0.30eV, not whether it's 0.220eV or 0.216eV. As a side note: Basic things like these seem to be just not intriguing enough for anyone to look into elaborately nowadays and that is why whenever one feels the urge to find out, we eventually end up at browsing publications from roughly the second half of the 20th century and reading off values from - sometimes coarsely - printed graphs or interpolating somewhat rough data points (I've had a go myself recently at theoretical photoisomerization cross sections and asymmetry parameters already...). And that is why many people tend to use and take for granted the same tabulated values - sometimes for decades even though they turn out to be not quite correct in the end... Anyway, I'm happy to know now where the core-hole linewidth values in Hephaestus come from (I sincerely dislike using/relying on such things when they seem to just "fall from the sky"). And if I may suggest this minor change for a future update to the software: Please amend the documentation in the local installation of Hephaestus with the paragraph detailing the core-hole lifetimes. Best regards Daniel
On 11/13/2017 11:15 AM, Daniel Przyrembel wrote:
Still I can't see any reference to 'Keski-Rahkonen and Krause' in
http://bruceravel.github.io/demeter/documents/Athena/hephaestus.html#absorpt...
Here is the relevant bit from Feff:
https://github.com/xraypy/feff85exafs/blob/master/src/COMMON/setgam.f
Note that that bit in Feff is less sophisticated than you might think. My memory (Matt or John might remember better) is that Steve Zabinski (main author of Feff6) "interpolated" those values from the plots in the K&R paper. This was done with a ruler back in the days before we had software tools for such chores. I am not saying that the values in setgam.f are wrong -- just not as precise as you might imagine.
B
-- Bruce Ravel ------------------------------------ bravel@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/ Beamline: https://www.bnl.gov/ps/beamlines/beamline.php?r=6-BM Software: https://github.com/bruceravel Demeter: http://bruceravel.github.io/demeter/ _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
On Mon, Nov 13, 2017 at 10:34 AM, Bruce Ravel
On 11/13/2017 11:15 AM, Daniel Przyrembel wrote:
Still I can't see any reference to 'Keski-Rahkonen and Krause' in
http://bruceravel.github.io/demeter/documents/Athena/hephaes tus.html#absorption
Here is the relevant bit from Feff:
https://github.com/xraypy/feff85exafs/blob/master/src/COMMON/setgam.f
Note that that bit in Feff is less sophisticated than you might think. My memory (Matt or John might remember better) is that Steve Zabinski (main author of Feff6) "interpolated" those values from the plots in the K&R paper. This was done with a ruler back in the days before we had software tools for such chores. I am not saying that the values in setgam.f are wrong -- just not as precise as you might imagine. https://www.bnl.gov/ps/beamlines/beamline.php?r=6-BM
Yes, I can verify that this was done. And also, the 1979 data from Krause and Oliver is probably preferred and should probably be used. For the K edges, the 1979 values are typically a bit lower than the 1974 (Keski-Rahkonen and Krause) data. Conveniently the 1979 data is tabulated, not graphed. I have put the 1974 values into the X-ray database within Larch ( http://xraypy.github.io/xraylarch/xray/index.html and https://github.com/xraypy/xraylarch/tree/master/plugins/xray) which is also in scikit-beam database (https://github.com/scikit-beam/XrayDB). Adding the Krause and Oliver values (and making those the default) would be great. Anyone up for scanning the PDF of Krause and Oliver and cleaning up the data into machine readable values like a spreadsheet? If so, I'd be happy to add them to the database. --Matt
Spreadsheet attached...Adobe did most of the work... On 11/13/2017 11:13 AM, Matt Newville wrote:
Anyone up for scanning the PDF of Krause and Oliver and cleaning up the data into machine readable values like a spreadsheet? If so, I'd be happy to add them to the database.
--Matt
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participants (4)
-
Bruce Ravel -
Daniel Przyrembel -
Matt Newville -
Robert Gordon