# Sum Over States with damping - another question

*From*: <gustavo!at!mercury.chem.pitt.edu>
*Subject*: Sum Over States with damping - another question
*Date*: Sun, 16 Nov 2003 22:45:29 -0500 (EST)

Dear CCL Readers,
I would like modify my original question. My problem is
that I am obtaining negative values for the imaginary part
of gamma(-w;w,w,-w). Can someone explain the meaning of a
negative value of this imaginary part?
Thank you very much in advance. I will summarize if I
receive any answer.
Sincerely yours,
Gustavo L.C. Moura
gustavo!at!mercury.chem.pitt.edu
> Dear CCL readers,
> I am interested in doing Sum Over States calculations of
> absorption of two photons. I have read several papers including
> the paper by Orr and Ward in Molecular Physics 20, 513 (1971).
> When comparing equation 43c from Orr and Ward with the equation
> in more recent papers that cite Orr and Ward, I found different
> signs in front of the damping factors (they are all negative).
> My question is: can anyone explain the discrepancy in these
> signs?
> Thank you very much in advance.
> Sincerely yours,
> Gustavo L.C. Moura
> gustavo!at!mercury.chem.pitt.edu