Dynamics of Energy Transfer in Van Der Waals Molecules of s-Tetrazine and Argon

Abstract

Energy conversion in the photoexcited van der Waals complex T.Ar of s-tetrazine and argon has been investigated in a supersonic jet by using the technique of laser-induced fluorescence. Time-resolved experiments on a picosecond timescale were performed in combination with steady-state measurements of the dispersed fluorescence. The temporal intensity profiles of selectively detected emission bands provide a detailed picture of the pathways (i.e. the proper succession of states) and the dynamics of intramolecular vibrational redistribution (IVR) and vibrational predissociation (VP) in the lowest excited singlet state of the complex. These processes have been studied by selectively pumping the levels $\overline {16} {a^2},{\bar 4^1},\bar 6{a^2}$ and $\bar 6{b^2}$ of the complex (a bar is used to assign vibronic states of the complex). The rates of IVR are in the range 5 × 10⁷ − 2 × lO⁹s⁻¹ and the rates of VP are between 5 × 10⁸ and 3 × l0⁹s⁻¹.