Hi Matt, Indeed, in my experience (which is limited to one beamline at one synchrotron facility for P XAS), once it is calibrated, the energy selection tends to be quite stable, so I think you're on-target there. The trouble I still run into, though, is comparability of data between studies.
Hi Mike, On Tue, May 5, 2020 at 10:56 PM Mike Massey wrote: > On a tangentially related topic, I find that phosphorus K-edge XAS energy > calibration conventions are still in a bit of a "Wild West" state, with a > wide variety of materials and values in use for energy calibration. As an >
For elements like P and S, people often use the energies of peaks. These are more immune to noise, energy-resolution effects and overabsorption than inflection points are. For instance, on ALS 10.3.2, I used the sulfate peak of gypsum set at 2482.74eV. I forget where I got that number.
Dear all This is an excellent thread. Just to give some background literature, you will be aware of the calibration of X-ray energies by diffraction (either like Kraft or better accuracy from the NIST group and Dick Deslattes, etc). This remains the best method for beamline calibration, though
Hi Mike, Matthew, On Thu, May 7, 2020 at 5:55 PM Mike Massey wrote: > I agree Matthew, I also tend to use the primary K-edge peak for P > calibration, but one issue to be wary of is attenuation/flattening of the > primary peak (if one is using a concentrated sample). > > Gypsum sounds like a
Hello, all. It's been a long time since I've been in touch. Yes, energy calibration is always an issue. Its especially important for lower-Z XAFS. I feel that edge and transition energies should be recorded, but depending on the beamline and facility the absolute calibrations are hard to
Hello everyone, In my experience, it is best to stay away from sulfate which has a hugely intense peak subject to self absorption. At SSRL, we advice users to choose Sodium Thiosulfate with the low lying and sharp S-S sigma star peak at 2472.02 eV and Tetraphenyl phosphonium bromide at 2146.96 eV
I agree Matthew, I also tend to use the primary K-edge peak for P calibration, but one issue to be wary of is attenuation/flattening of the primary peak (if one is using a concentrated sample). Gypsum sounds like a good material to use for S, since it is commonly available and probably not too