Vibron-mediated electronic relaxation in crystalline chlorine Original Research Article

Luminescence decay of thin solid films of molecular chlorine exhibit distinctly non-exponential temporal behavior following pulsed ultraviolet laser excitation. The temporal characteristics are dependent on sample temperature and laser fluence in the range 11–80 K. This behavior is attributed to internal conversion from the first excited A′(3Π2u) electronic state to the ground state, which is accelerated by phonons and localized vibrational excitons (vibrons). This unusual mechanism of electronic relaxation is consistent with a recent theoretical model for the mechanism of explosive desorption of cryogenic films.