Is it possible to combine FON and the Raman calculations?

Just Got Here

9:34:24 PM PDT - Sun, Apr 30th 2017
Dear NWChem developers and users, I am trying to calculate the raman spectra for a molecular with fractional numbers of electrons by combining FON and Raman calculations. I try to put the raman block after the FON input, but running it will return a error. I am wondering whether it is possible to calculate raman spectra for a molecular with fractional numbers of electrons using nwchem? If so, what is the correct input for such kind of calculations? Any advice will help! Thanks in advance. Best regards! Zhuang

Forum Regular

6:31:19 AM PDT - Mon, May 1st 2017
This is not possible within NWChem. The coupled-perturbed Kohn-Sham equation solver assumes integer occupations of the orbitals. The error you are getting is most likely from when the code checks to see if you are at a stationary solution of the SCF equations. Since you performed your SCF with fractional occupation numbers and the code checks the solution using integer occupation numbers, it finds that you are not at a stationary solution and aborts.