State-selective studies of T→R, V energy transfer: The H+CO system

Abstract

Articles you may be interested inA guidedion beam study of the hydrogen atom transfer reaction of stateselected N+ 2 with H2 at collision energies ranging from subthermal to 2 eV (c.m.)A twolaser pulseandprobe study of TR, V energy transfer collisions of H+NO at 0.95 and 2.2 eV Collisional energy transfer from H atoms to CO (v = 0, J"", 2) has been studied at a collision energy of 1.S8 ± 0.07 eV by photolyzing H 2 S at 222 nm in a nozzle expansion with CO and probing the CO(v", J") levels using tunable VUV laser-induced fluorescence. The ratio CO (v" = 1) ICO (v" = 0) is found to be 0.1 ± 0.008. The rotational distribution of CO(v" = 0) peaks atJ" ,11 and decays gradually; population is still observed atJ">4S. The rotational distribution of CO (v" = 1) is broad and peaks near J" = 20. The experimental results are compared to quasiclassical trajectory calculations performed both on the H + CO surface of Bowman, Bittman, and Harding (BBH) and on the surface of Murrell and Rodriguez (MR). The experimental rotational distributions, particularly those for CO (v" = 1), show that the BBH surface is a better model than the MR surface. The most significant difference between the two surfaces appears to be that for energetically accessible regions of configuration space the derivative of the potential with respect to the CO distance is appreciable only in the HCO valley for the BBH surface, but is large for all H atom approaches in the MR potential. Because the H-CO geometry is bent in this valley, vibrational excitation on the BBH surface is accompanied by appreciable rotational excitation, as observed experimentally.

Rotationally and translationally resolved hot atom collisional excitation of the CO2 Fermi mixed bend/stretch vibrational levels by time-dependent diode laser spectroscopy

“…(6) The ratio of the collisional excitation probability for the Fermi mixed CO 2 ( 10°0102°0) states by H* atoms compared to 0* atoms decreases with increasing rotational quantum number, as expected based upon simple angular momentum considerations. The overall H* 10* excitation probability ratio for all 10°0102°0 rotational levels is 0.96 ± 0.24.…”

“…(6)] or vibrationally inelastic scattering from the low-lying 0110 bend state (Eq. (7)] plays a significant role in the collision dynamics:…”

The analytical representation of electronic potential-energy surfaces

“…Bowman et al (1985). 'Murrell and Rodriguez (1986); Chawla et al (1988). dition, many of the HCO and COH saddle-point frequencies match BBH quite closely, even though they were not specifically optimized.…”

CO and H2O vibrational emission toward Orion Peak 1 and Peak 2

“…Green & Thaddeus (1976) have shown that collisional rates for rotational transitions at 100 K for CO-H are lower than for CO-H 2 , but at higher temperatures results are uncertain due to the presence of resonances in CO-H rotational inelastic scattering that are a consequence of the formation of the HCO intermediate complex (Lee & Bowman 1987). On the other hand, experimental studies of the CO v = 1 rotational distribution in CO-H collisions have been only performed for well defined and high kinetic energies of H and low rotational temperatures of CO (e.g., Wight & Leone 1983;Chawla et al 1988;McBane et al 1991), so that thermal averages cannot be derived from these data. Theoretical efforts to fit those measurements underestimate the populations of low J in v = 1 relative to those of higher J Fig.…”