Intersystem Crossing of 2-Methlypyrazine Studied by Femtosecond Photoelectron Imaging

2-methylpyrazine was excited to the high vibrational dynamics of the S-1 state with 260 nm femtosecond laser light, and the evolution of the excited state was probed with 400 nm light. Because it was unstable, the S-1 state decayed via intersystem crossing to the triplet state T-1, and it may have decayed to the ground state S-0 via internal conversion. S-1-to-T-1 intersystem crossing was observed by combining time-resolved mass spectrometry and time-resolved photoelectron spectroscopy. The crossover time scale was 23 ps. Rydberg states were identified, and the photoelectron spectral and angular distributions indicated accidental resonances of the S-1 and T-1 states with the 3s and 3p Rydberg states, respectively, during ionization.

Automated summary

This study investigates the excited state dynamics of 2-methylpyrazine and observes its decay pathways via intersystem crossing and internal conversion.