Electronic relaxation in the S1 state of jet-cooled p-alkoxyanilines

Fluorescence lifetimes of various vibronic levels of jet-cooled p-aminophenol (AP), p-methoxyaniline (MA), p-ethoxyaniline (EA), and p-aminophenol-Ar-1 complex are reported. The lifetimes were invariant for the first few hundred wavenumbers and started lowering at around 1270 cm(-1) for AP, around 900 cm(-1) for MA, and around 660 cm(-1) for EA. Additionally, mode-specific lowering of lifetimes was observed around 850 cm(-1) region for AP and MA. Fluorescence lifetimes of the vibronic levels of AP-Ar-1 complex were marginally lower than those for the corresponding parent molecule excitations. (C) 1999 Elsevier Science B.V. All rights reserved.