Rotational energy transfer in collisions between CO and Ar at temperatures from 293 to 30 K

Abstract

Experimental measurements and theoretical calculations are reported for rotational energy transfer in the Ar-CO system. Experiments were performed in cold uniform supersonic flows of Ar, using an infrared -vacuum ultraviolet double resonance technique to measure absolute state-to-state rate constants and total relaxation cross sections for rotational energy transfer within the (v = 2) vibrational state of CO in collision with Ar at temperatures from 30.5 to 293 K. Close-coupled calculations were also performed using a recent potential energy surface (Y. Sumiyoshi and Y. Endo, J. Chem. Phys. 142 (2015) 024314). Very good agreement is obtained between measured and calculated values.

Low Temperature Kinetics of the Reaction Between Methanol and the CN Radical

“…Rowe and co-workers 26 developed the use of CRESU flows to study gasphase kinetics and this technique has since been used to characterize many ion-neutral reactions, [27][28][29][30][31] neutral-neutral reactions, 8,12,[32][33][34][35][36] and collisional energy transfer processes. [37][38][39][40] A detailed summary of the reactions studied using the CRESU technique was published recently. 41 Radical-neutral reactions are thought to be an important destruction route for gas-phase methanol at low temperatures.…”

An Efficient Statistical Method to Compute Molecular Collisional Rate Coefficients

“…Nowadays theoretical data can be obtained for neutral -closed shell -diatomic and polyatomic molecules colliding with atoms or light diatomic perturbers like H 2 at the full quantum time-independent close-coupling level of theory. In addition, accuracy can be inferred by comparing calculations directly with state-to-state experimental data thanks to recent developments in double resonance (Mertens et al 2017) and crossed-beam techniques (Vogels et al 2015;Chefdeville et al 2015). Such comparisons have demonstrated the high-accuracy of modern computations based on state-of-the-art potential energy surfaces.…”

Rotational relaxation of H2S by collision with He

“…We then compare our results with the only experimental data available of Ball et al (1999) for the 1 10 → 1 01 transition of H 2 S colliding with He. As a matter of fact, PES calculations have reached a very high level of accuracy, which is illustrated by the very good agreement between theory and experiment obtained in several recent studies dedicated to the H 2 -CO (Faure et al 2016), D 2 -CO (Stoecklin et al 2017), Ar-CO (Mertens et al 2017), NO+O 2 (Gao et al 2018), and ND 3 -D 2 (Gao et al 2019) systems. Ball et al (1999) did not obtain state-to-state rate coefficients but gave instead depopulation Boltzmann averaged cross sections for the rotational transition 1 01 → 1 10 as a function of temperature.…”