Time evolution of conjugated systems in excited states by surface hopping nonadiabatic molecular dynamics

Exploration of the electronic surfaces represents one of the most difficult problems in molecular calculations. The first part of the project is to compare the electronic absorption spectra of studied molecules obtained by semiempirical MNDO/OMx methods with the same spectra calculated by ab initio methods and/or experimental data. The stationary spectra of selected molecules will be determined using a broad spectrum of ab initio methods. These results help to understand the electronic structure with emphasis on the choice of correct active spaces for ab initio and semiempirical methods. The second part is connected with the method of Tully surface hopping for characterization of the dynamics of studied molecules. Here two approaches will be used: one based on Newton-X software co-developed by one of the applicants, which can be coupled with many ab initio quantum chemical packages and another based on MNDO99 software where surface hopping is also implemented. We also plan some extention and further improvement of the efficiency of the Newton-X implementation of surface hopping.