研究目的

To investigate the nonradiative decay mechanism of S1 excited cytosine and the effect of different ring substituents, combining jet-cooled spectroscopy with CASPT2//CASSCF computations of the decay paths for a set of eight cytosine derivatives.

研究成果

The combination of experiment and theory has allowed us to locate and characterize the CI responsible for ultrafast decay of jet-cooled cytosine derivatives excited at the red edge of their absorption spectra. The excited-state calculations along the C5?C6 path reproduce the experimental trend for the six unclamped derivatives, which allows us to unambiguously assign the decay mechanism following S0→S1 excitation at the long-wavelength end of the absorption spectrum.

研究不足

The study focuses on low-energy excitation with ns and ps lasers, and the findings may not fully extrapolate to higher excitation energies. The computational methods may not capture all substitution effects accurately due to convergence problems with larger active spaces.