Dear Sirs: I'm working with radical cations and I'm trying to compute their UV-VIS spectra with TD DFT with Gaussian 98. We have tried as a bench mark the OH radical and we have some troubles (we got an error message with large basis sets and when we succeded in getting a result one of the excitation energies was absurd) Any suggestion will we helpfull Thank you very much Yours sincerely Alejandro Crespo