CCL:G: TD DFT percent contributions

 Sent to CCL by: "Jason D'Acchioli" [jdacchio/a\gmail.com]
 Hi all,
 	I have a technical question regarding the interpretation of TD-DFT results from
 any program, but using Gaussian as the most readily-available example. A typical
 Gaussian (G09) output lists several excitations calculated.
  Excited State   8:      Singlet-A      3.2952 eV  376.26 nm  f=0.1749
 <S**2>=0.000
       95 ->102        -0.11772
       96 ->100         0.64507
       98 ->101        -0.23293
 	I've seen several posts on calculating the percent contributions of orbitals to
 the specified transitions, as
 (coefficient)^2 x 2 x 100 = percentage. So, for 96 -> 100 above, the
 contribution would be 82%. What about the negative signs? From similar posts on
 here, I've seen that the sign is ignored. However, at the PC Gamess/Firefly
 site, it is stated that negative contributions should be subtracted (http://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C34df668afbHW-6978-840+00.htm).
 Can someone help with this?
 Thanks,
 Jason
 *******************************************
 Jason D'Acchioli
 Assistant Professor of Chemistry
 University of Wisconsin-Stevens Point
 2001 Fourth Avenue
 Stevens Point, WI 54481
 http://chemdac.uwsp.edu