Posted by Ignacio on March 22, 2010 at 12:09:49:
If I understand it correctly, in Molcas 7 there are at least to ways to include an external set of point charges (point charges is all I'm interested in at the moment) that polarize the electron density. One is adding XField in GATEWAY, the other is the ESPF module. Is there any difference between them that I should be aware of? Is the charges' effect properly included in all subsequent calculations (RASSCF, CASPT2, ALASKA) in both cases?
As for the final interaction energy between the nuclei+electrons and the external point charges, this value was not provided with XField in Molcas 6, and it seems to be still the case (one has to calculate the potential with EPot in SEWARD). With ESPF an interaction energy is given after RASSCF, but I understand is an "approximated" energy, calculated with the fitted mono- and dipoles of the QM molecule. Is there any easy way te get the "real" electrostatic interaction energy between the QM molecule and the external charges?
Finally, the "ESPF analysis" is reported after a RASSCF calculation, but not after CASPT2. Is there some keyword to add for CASPT2?