[Ifeffit] Difference spectra

[sb2c08 at gmail.com]

Hi,
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?
   Thanks for any help or suggestions,
   Stu