engleski

Comparison of TD-DFT and MRCI calculated vertical excitation energies for formamide and its cationized forms

The vertical excitation energies for formamide and its adducts with H+, Li+ and Na+ have been calculated using time dependent DFT method. The results are benchmarked against MR-CISD and MR-CISD+Q methods, which were previously shown to give a proper description of the major features in electronic spectra of the parent molecule. The calculations were performed at the same ground state equilibrium geometries (optimized with MP2/cc-pVTZ method). Analysis of the results reveals that TD-DFT satisfactorily reproduces energies of the valence excited states. However, their performance in describing excitation energies of the Rydberg states is found to be very poor. The performance of the TD-DFT in calculating geometries of the first excited state of the studied species will be also discussed.

DFT method; formamide; complexation; excited states

nije evidentirano