MEASUREMENT OF THE NU(3) FUNDAMENTAL TRANSITION-MOMENT AND VIBRATIONAL-RELAXATION RATES OF THE CD3 RADICAL

Diode laser absorption spectroscopy was used to measure the transition dipole moment for the v(3) (degenerate asymmetric stretch) fundamenta l vibration of CD3 produced by the 193-nm photodissociation of acetone -d(6). The time evolution of the ground state absorption was used to m easure the vibrational relaxation rates from the manifold of excited v ibrational states to the ground state of CD3 following collisions with various bath gases. The transition dipole moment was determined to be 0.030+/-0.002 D and the vibrational relaxation coefficients were dete rmined to be (2.5+/-0.2)x10(-13) for argon, (2.6+/-0.2)x10(-13) for he lium, (3.15+/-0.2)x10(-13) for nitrogen, and (4.3+/-0.5)x10(-12) for a cetone-d(6) in units of cm(3) molecules(-1) s(-1). Results are compare d to literature values for CH3 and the mechanism of the relaxation is discussed. (C) 1996 American Institute of Physics.