NONRADIATIVE TRANSITIONS IN COLLISIONLESS PERDEUTEROBENZENE

The rates and quantum yields of internal conversion and intersystem crossing have been measured for several vibronic levels of perdeuterobenzene. The molecule existed in the cold and collisionless environment of a supersonic expansion, while the excited state dynamics were measured by time‐resolved multiphoton ionization mass spectrometry. It is found that the onset of rapid internal conversion is lowered by deuteration to ∼2400 cm−1 as compared to 3300 cm−1 for benzene‐h6.