Direct formation of CH2 ((b)over-tilde(1)B(1)) in the near-UV photodissociation of diazirine

Abstract

A prompt, long-lived, and red fluorescence has been observed in the photodissociation of the jet-cooled diazirine (H2CN2) excited at the origin (322.96 nm) of the S-1 <-- S-0 transition. The fluorescence decays (similar to 16 mu s) and range (> 575 nm) indicate that the emitting species is the electronically excited singlet methylene, CH2 ((b) over tilde(1)B(1)). The linear dependence of the fluorescence intensity on the photolysis laser power strongly supports that the fluorescing CH2 ((b) over tilde(1)B(1)) is produced directly from the first excited singlet state of diazirine. The observation that the fluorescence appears in the visible wavelength region indicates that the CH2 ((b) over tilde(1)B(1)) fragments are highly vibrationally excited. (C) 1998 Elsevier Science B.V. All rights reserved.