Warning, anecdote ahead! (and this wasn't the point of my original post...)
I get better (flatter difference plot) fits with SRM676A using charged atoms (Al+3, O-2) than I do with neutral. (Co Ka, lab BB diffractometer) https://imgur.com/a/83s1Bpz (sqrt scale) I intend on looking in more depth (the pics above are the current extent of my investigation), as I'm trying to calibrate some new QPA QC standards, and found some issues, so I ended up wandering into a can of worms... Matthew On Wed, 22 Feb 2023 at 02:11, Toby, Brian H. <t...@anl.gov> wrote: > I am going to make the comment that (A) neutral atom form factors are > probably closer to the actual electron distribution in most materials where > there is significant covalent bonding (~= almost everything) and (B) even > if that were not true, the difference between O, O1- and O2- is probably > pretty minor for powder diffraction, so the choice does not matter. Except > at very low angle, the form factor curves are just about the same for > ionized atoms as neutral ones. (This is understandable since ionization > only affects the outer shell electrons.) So, other than a small change in > the first reflection or two, easily swamped by experimental artifacts, one > just does not see any difference. > > I personally use only neutral atom form factors. > > Brian > > > On Feb 21, 2023, at 4:10 AM, Matthew Rowles <rowle...@gmail.com> wrote: > > Thanks all > > It looks like fat fingers all around! > > W&K doesn't contain O2-, does contain O- > RR&G _does_ contain O2-, doesn't contain O- (every version of the > waasameir data I've found online has this typo, so I'm pretty sure they're > all the same file.) > > Now just to cross-check the data to see if they're the same (and > actually _read_ the papers) > > I'll also check out the other papers, and start looking for some N3-. > > Thanks > > > Matthew > > > > > > > > > On Tue, 21 Feb 2023 at 17:44, Kern, Arnt <arnt.k...@bruker.com> wrote: > >> Hello Daniel, hello all! >> >> >> >> Daniel, you are right. I just obtained the Hovestreydt paper, he actually >> published a 9 coefficients representation. >> >> >> >> My apologies! >> >> >> >> Cheers, >> >> >> >> Arnt >> >> >> >> >> -Bruker Confidential- >> >> *Von:* rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> *Im Auftrag >> von *Többens, Daniel >> *Gesendet:* Dienstag, 21. Februar 2023 09:58 >> *An:* rietveld_l@ill.fr >> *Betreff:* Re: scattering factor for O2- ? >> >> >> >> Hello Arnt, >> >> I believe you are probably mistaken. The file at GitHub cites at the >> source of most of its scattering factors either the paper of Waasmaier & >> Kirfel ("New Analytical Scattering Factor Functions for Free Atoms and >> Ions", D. Waasmaier & A. Kirfel, Acta Cryst. A 95) or the International >> Tables, with the sole exception of "Fit for O1- based on the tabulated >> values of Table 2 (D. Rez, P. Rez & I.Grant, Acta Cryst. (1994), A50, >> 481-497)." >> >> This is most certainly a typing error, as neither of the former two >> contains values for O2-, while the paper of Rez does not contains values >> for O2-, but not for O1-. I would be very surprised if the values there >> were not fitted to the table of Rez. >> >> Just for the sake of completeness, there are at least two more papers >> with scattering factors for O2-: >> >> Schmidt, P.C., K.D. Sen, and A. Weiss, The Spherical Crystal-Potential >> and Physical-Properties of Ions in Crystals - a Hf-Calculation for the >> 10,18, and 36-Electron Closed Shell Ions of X-Ray-Scattering Factors, >> Diamagnetic Susceptibilities, and Dipole Polarizabilities. Berichte Der >> Bunsen-Gesellschaft - Physical Chemistry Chemical Physics, 1980. 84(12): p. >> 1240-1251. >> >> Azavant, P. and A. Lichanot, X-Ray-Scattering Factors of Oxygen and >> Sulfur Ions - an Ab initio Hartree-Fock Calculation. Acta Crystallographica >> Section A, 1993. 49: p. 91-97. >> >> Good Luck to everyone out there, >> Daniel Többens >> >> Am 21.02.2023 um 07:52 schrieb Kern, Arnt: >> >> Hi Matthew, >> >> >> >> I am pretty sure, this is >> >> >> >> “On the atomic scattering factor for O2-“ >> >> E. Hovestreydt >> >> >> >> Acta Cryst. (1983). A39, 268-269 >> >> https://doi.org/10.1107/S0108767383000550 >> >> >> >> I don’t have the paper at hand, unfortunately. >> >> >> >> Cheers, >> >> >> >> Arnt >> >> >> >> >> >> >> -Bruker Confidential- >> >> *Von:* rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> >> <rietveld_l-requ...@ill.fr> *Im Auftrag von *Matthew Rowles >> *Gesendet:* Dienstag, 21. Februar 2023 01:38 >> *An:* RIETVELD_L Distribution List <rietveld_l@ill.fr> >> <rietveld_l@ill.fr> >> *Betreff:* scattering factor for O2- ? >> >> >> >> **EXTERNAL EMAIL** >> >> Hi all >> >> >> >> I've been looking at atomic scattering factors recently, and in >> particular, the 11-coefficient parameterisation by Waasmaier and Kirfel [1]. >> >> >> >> In their paper, they give a parameterisation for O and O-, but in tables >> I can find online (eg libdiffpy/f0_WaasKirf.dat at master · >> diffpy/libdiffpy (github.com) >> <https://github.com/diffpy/libdiffpy/blob/master/src/runtime/f0_WaasKirf.dat>), >> there is also an entry for O2-. >> >> >> >> Does anybody know where this came from? >> >> >> >> Thanks >> >> >> >> Matthew >> >> >> >> >> >> [1] D. Waasmaier & A. Kirfel, New Analytical Scattering Factor Functions >> for Free Atoms and Ions for Free Atoms and Ions, Acta Cryst. (1995). A51, >> 416-413 >> >> >> >> >> >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> >> <alan.he...@neutronoptics.com> >> >> Send commands to <lists...@ill.fr> <lists...@ill.fr> eg: HELP as the subject >> with no body text >> >> The Rietveld_L list archive is on >> http://www.mail-archive.com/rietveld_l@ill.fr/ >> >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> >> >> >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> Please do NOT attach files to the whole list < >> alan.he...@neutronoptics.com> >> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body >> text >> The Rietveld_L list archive is on >> http://www.mail-archive.com/rietveld_l@ill.fr/ >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > >
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