State-to-State Rate Constant Calculations for V−V Energy Transfer in CO−N₂ Collisions

Abstract

Single and multiquantum vibrational relaxation of low and highly vibrationally excited levels of CO in collisions with N 2 is studied within the semiclassical coupled state method. The dynamics is followed using ab initio interaction potential for the short-range interaction and updated multipole expansions for the long range interaction. Compared to the previous study, a better agreement with the available experimental rate constants is obtained, particularly in the critical low temperature regime down to T ) 80 K. Remarkable corrections are found for rate constants for single and multiquantum transitions between highly excited CO and N 2 molecules.

Full Dimensional Potential Energy Function and Calculation of State-Specific Properties of the CO+N2 Inelastic Processes Within an Open Molecular Science Cloud Perspective

“…Rate coefficients (logarithmic scale) plotted as a function of temperature for the CO(1)+N 2 (0) → CO(0)+N 2 (1) transition. Present work results (solid line) compared to the experimental ones up to 300 K of Allen and Simpson (1980) (red circles) and those calculated in Kurnosov et al (2003) using different potentials (dashed lines with points).…”

“…For comparison, the same Figures show the experimental data (Sato et al, 1969; von Rosenberg et al, 1972; Mastrocinque et al, 1976; Allen and Simpson, 1980), when available, together with previous theoretical results (Kurnosov et al, 2003).…”

Falloff curves for the unimolecular decomposition of two acyl radicals: RCO (+M) → R + CO (+M) by pulsed laser photolysis coupled to time‐resolved infrared diode laser absorption

“…Due to the subsequent relaxation, the population of v = 0 would increase with a time constant governed by the rate constant k Q for quenching of CO (v = 1) by the bath gas, mainly N 2 (k Q = 5.52 × 10 −15 cm 3 molecule −1 s −1 for N 2 at 300 K [37]) and by the aldehyde molecules. For a typical experiment in 10 Torr N 2 , the quenching constant for N 2 is k Q ∼ = 1600 s −1 , i.e.…”

Vibrational Energy Transfer in CO+N2 Collisions: A Database for V–V and V–T/R Quantum-Classical Rate Coefficients

“…For this reason, the quantum-classical (QC) approach, sometimes also referred to as semiclassical, has been used over the years for the description of inelastic scattering in a variety of diatom–diatom systems: N +N [ 10 , 11 , 12 , 13 ], CO+CO [ 14 , 15 ], N +CO [ 11 , 16 , 17 , 18 ], O +O [ 19 , 20 , 21 ], etc. leading, in some cases, to the creation of large databases for V–V rate coefficients.…”

“…Furthermore, as shown for N -N collisions [ 27 , 28 ], in general, ab initio based potentials might be inaccurate when very large initial separation distances of the colliding partners are required: the number of ab initio points needed even for an approximate description of all long-range configurations is still prohibitive and interpolation procedures might produce spurious effects [ 29 ]. On the other hand, analytical and/or semiempirical potentials, often simply constructed as a sum of repulsive short-range and attractive long-range components of the interaction potential, have been proposed [ 11 , 17 ] and, provided that all interaction regions (long-range, interaction wells, and repulsive walls) are appropriately taken into account, they are found to reproduce V–V and V–T/R rate coefficients quite effectively.…”