State-resolved vibrational, rotational, and translational energy deposition in CO2(0001) excited by collisions with hot hydrogen atoms

Abstract

Time-domain tunable diode laser absorption spectroscopy has been used to measure rotationally resolved transient absorption line shapes and nascent rotational populations for CO2 molecules excited into the (0001) vibrational state by collisions with translationally hot hydrogen atoms. High-accuracy measurements were made at both 292 and 223 K, providing information about the initial-state dependence of the collision dynamics and about the (temperature-independent) state–to–state scattering cross sections. The nascent rotational population distribution is found to be nearly independent of temperature, indicating broad rotational inelasticity in the 0000→0001 scattering process. The nascent populations and transient linewidths are interpreted in terms of two separate theoretical models which lend substantial insight into the H–CO2 collision dynamics.