Time Dependent Thermal Lensing Measurements of V-T Energy Transfer From Highly Excited NO2

BEATRIZ M. TOSELLI; THERESA L. WALUNAS; JOHN R. BARKER

AMER INST PHYSICS

Año: 1990 p. 4793 - 4793

The time dependent thermal lensing technique has been used to measure the vibrationalrelaxation of N02 (initially excited at 21 631 cm - I) by Ar, Kr, and Xe. The energy transferanalysis was carried out in terms of «t::..E», the bulk average energy transferred per collision.This quantity was found to have a very strong dependence on vibrational energy, with amarked increase at energies greater than about 10 ()()() cm -I, where several electronic excitedstates eB2, 2BI, and 2A2) mix with the ground state eA I ). This effect may be due to largeamplitude vibrational motions associated with the coupled electronic states. Even at lowenergies, deactivation is faster than in other triatomic systems, probably because N02 is anopen shell molecule and electronic curve crossings provide efficient pathways for vibrationaldeactivation. The V-Trate constant for deactivation ofN02(01O) by argon is estimated to be(5.1 ± 1.0) X 10- 14 cm3 s