Study on fluorescence spectra of the four heterocyclic compounds in solution

The fluorescence spectra of the four compounds have been studied. Geometric configurations of the four compounds have been optimized by semi-empirical mothod RHF/AM1 of quantum chemistry. There is no imaginary frequency in vibrational analysis. Their fluorescence spectra have also been calculated by RHF/CIS. The results of calculation in solution are better agreement with experimental values than in gas phase.