On 05/30/2016 01:25 PM, sb2c08@gmail.com wrote:
We recently collected laser pump-probe XAS data out to k=9. The process to get the excited state is to take the laser off minus the laser on data. I'm a little unsure in terms of trying to fit the difference EXAFS and is it possible via Athena? So far I model the EXAFS of the excited state and take away from the ground state model and compare visually. The only way I can think is to work out the % conversion and add that % of laser off back to the difference data in order to get the real EXAFS of the excited state, which can be fitted through Athena. But this is really difficult and probably inaccurate?
Of course it's not possible to fit and EXAFS spectrum in Athena. Artemis is the program for fitting the EXAFS. I am unclear on what you have tried so far, so I am a little unsure what kind of answer you are looking for. Artemis was not really written with your sort of experiment in mind. That said, if your problem is fit some theory from Feff to a measured spectrum with some fitting model -- that is what Artemis is for. As with any difficult problem, you need to understand your data and your model and you need to understand Artemis well enough to implement the fit. But there is no magical, hidden button that says "fit my pump-probe data." B -- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Science Group at NSLS-II Building 535A Upton NY, 11973 Homepage: http://bruceravel.github.io/home/ Software: https://github.com/bruceravel Demeter: http://bruceravel.github.io/demeter/