Intersystem crossing and internal conversion in propynal vapor

Abstract

A kinetic model that describes the energy flow through a propynal molecule which is initially excited to the ¹A″ state has been proposed. Eight decay rates contained in this model have been determined from Stern‐Volmer plots, quantum yields, and integrated absorption coefficient measurements in the pressure region from 0.05 to 1 torr. Only forward rates were considered, and all pathways were found to be significant. In particular, both intersystem crossing and internal conversion from the ¹A″ state were observed under both collisional and collision free conditions. However, intersystem crossing appears to predominate in each case. A model previously proposed to describe collisional quenching in propynal must be slightly modified in order to be consistent with these observations.