I have been trying for a while to excite a molecule from a triplet ground state surface to a singlet excited state using Gaussian09 using the following input keywords.
#cam-b3lyp/gen td(singlet,nstates=10,root=1) scrf(smd, read, solvent=n,n-DiMethylFormamide)
triplet O2
0 3
8 25.136529024 28.339914299 -0.193692832
8 26.017258738 29.165728406 -0.344116694
O 0
6-31+G**
****
Everytime I have landed on a triplet excited state rather than a singlet surface.