Dynamics of weak and strong collisions:: Highly vibrationally excited pyrazine (E=37900 cm-1) with DCl+

The outcome of energy transfer due to single collisions between highly vibrationally excited pyrazine (E = 37900 cm(-1)) and DCl is measured for the appearance of individual low-J rotational states of DO using high-resolution transient IR absorption. Appearance profiles from double-Gaussian transient lineshapes were measured for a number of DCl states with J = 2-12. These data give information on the recoil velocity distributions, appearance rates, and populations of individual states of the scattered molecules. These data complement previous studies on high-J state DCl scattering (Li, Z.; Korobkova, E.; Werner, K.; Shum, L.; Mullin, A. S. J. Chem. Phys. 2005, 123, 174306), and together, they provide a full description of the V-RT collisions with DCl that quench pyrazine(E). Scattered DCl (v = 0) molecules with J = 2-21 are rotationally hot with T-rot = 880 +/- 100 K. Center-of-mass translational energy distributions are T-rel similar to 700 K for J < 15. Broader velocity distributions are observed for the J = 15-20 states. The rate constant for V-RT energy transfer is 4.6 x 10(-10) cm(3) molecule(-1) s(-1). This value is a lower limit to the overall rate constant for energy transfer and corresponds to similar to 85% of the Lennard-Jones collision rate. We estimate scattering into the DCl (v = 1) state occurs in similar to 1% of collisions. The energy transfer probability distribution P is presented and yields Delta E) = 888 cm(-1).