Hi, Ah, Krause et al *do* use hbar, not h, so yeah With gamma = 0.2 eV, and h ~= 4.13567e-15 eVs (hbar ~ 6.582e-16 eVs), then lifetime is ~3 fs.
That is probably the mistake that hephaestus is making too. FWIW, we are not currently, but could be reporting core-level widths and lifetimes at https://xraydb.xrayabsorption.org/ On Mon, Sep 28, 2020 at 1:37 PM Matt Newville <newvi...@cars.uchicago.edu> wrote: > I believe it is using (or intends to use) > > lifetime = hbar /gamma > > which is what Krause et al give. With gamma = 0.2 eV, and hbar ~= > 4.13567e-15 eVs, then lifetime is ~20fs. > Maybe I'm missing something more subtle? FWIW, these reported numbers for > gamma in eV are described by Krause et al as "FWHM". > > --Matt > > > On Mon, Sep 28, 2020 at 1:13 PM Daniel Przyrembel < > daniel.przyrem...@fu-berlin.de> wrote: > >> Hi Matt, >> >> Thanks for the quick reply! >> However, I seem to not have made clear my concern... >> >> The widths in energy (eV) are fine. >> >> However, in "Hephaestus", the "souped-up periodic table for the X-ray >> absorption spectroscopist", these level widths in energy (eV) are also >> given as equivalent lifetimes (in fs), however incorrectly: A level width >> of ~0.2 eV in fact corresponds to a lifetime of ca. 3 fs, not ~30 fs as >> given there. >> >> Those lifetimes shown in Hephaestus all seem to be off by a general factor >> of 10. I guess that is just the energy width/lifetime conversion gone >> slightly wrong... >> I imagine I'm not the only one using Hephaestus as a convenient tool to >> look stuff up quickly, so I thought it might be useful to point out this >> flaw. >> >> Just to make sure, I have again imported the xraydb: That has not changed >> Hephaestus' behavior in terms of the lifetime info (I'm using the latest >> 64-bit version on Windows). >> >> >> > Hi Daniel, >> > >> > Thanks - that does seem wrong. FWIW, Larch uses XrayDB which uses >> > corehole >> > widths from Krause and Oliver for Z>10 and Keski-Rahkoken nand Krause >> for >> > Z<10. >> > For the F K edge, this give 0.2089 eV. For this or other core-hole >> > widths, >> > and assuming you have Python installed, try: >> > >> > ~> pip install xraydb >> > ~> python >> > >>> import xraydb >> > >>> xraydb.core_width('F', 'K') >> > 0.2089 >> > >> > Or install Larch and use >> > >> > ~> larch >> > larch> core_width('F', 'K') >> > 0.2089 >> > >> > >> > >> > On Mon, Sep 28, 2020 at 12:08 PM Daniel Przyrembel < >> > daniel.przyrem...@fu-berlin.de> wrote: >> > >> >> To Whom it may concern, >> >> >> >> I am quite sure there is a general lifetime/energy-width conversion >> >> error >> >> in Hephaestus: All core-hole lifetimes seem to come out too long by a >> >> factor of - as it seems exactly - 10: >> >> E.g. the lifetime of the F K-edge with a width of 0.25 eV is given as >> >> 25.30 fs instead of ca. 2.6 fs (width = h_bar / lifetime). >> >> >> >> This glitch was present in 0.9.25 already and, as I noticed after >> >> updating, prevails in 0.9.26. I have not tried earlier versions. >> >> >> >> Best regards, >> >> >> >> Daniel >> >> >> >> _______________________________________________ >> >> 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 >> >> >> > _______________________________________________ >> > 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 >> > >> >> >> _______________________________________________ >> 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 >> > > > -- > --Matt Newville <newville at cars.uchicago.edu> 630-252-0431 > -- --Matt Newville <newville at cars.uchicago.edu> 630-252-0431
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