TY - JOUR

T1 - Multi-temperature vibrational energy relaxation rates in CO2

AU - Kustova, E.

AU - Mekhonoshina, M.

N1 - Publisher Copyright: © 2020 Author(s).

PY - 2020/9/1

Y1 - 2020/9/1

N2 - Rates of vibrational energy relaxation in carbon dioxide are studied in the framework of the three-temperature kinetic-theory approach. Vibrational-translational transitions in the bending mode and inter-mode exchange of vibrational quanta are considered. In the zero-order approximation of the generalized Chapman-Enskog method, the energy relaxation rates in the coupled symmetric-bending and asymmetric modes are expressed in terms of thermodynamic forces similar to chemical reaction affinities, and a compact representation for the vibrational energy production rates is proposed. Linearized theory is developed, and analytical ratios of linearized relaxation rates to those defined by the original Landau-Teller (LT) theory are obtained. The relaxation rates are calculated using the Schwartz-Slawsky-Herzfeld (SSH) and forced harmonic oscillator models for the vibrational energy transition probabilities in the temperature range 200 K-10 000 K. For inter-mode exchanges, using the SSH theory yields significantly underpredicted relaxation rates. The ranges of applicability for the LT formula and linearized theory are estimated; the original LT formula for inter-mode vibrational energy exchanges is not capable of accounting for the excitation of both vibrational modes; linearized models yield better results. Possible steps for improving the numerically efficient LT model are proposed. Published under license by AIP Publishing.

AB - Rates of vibrational energy relaxation in carbon dioxide are studied in the framework of the three-temperature kinetic-theory approach. Vibrational-translational transitions in the bending mode and inter-mode exchange of vibrational quanta are considered. In the zero-order approximation of the generalized Chapman-Enskog method, the energy relaxation rates in the coupled symmetric-bending and asymmetric modes are expressed in terms of thermodynamic forces similar to chemical reaction affinities, and a compact representation for the vibrational energy production rates is proposed. Linearized theory is developed, and analytical ratios of linearized relaxation rates to those defined by the original Landau-Teller (LT) theory are obtained. The relaxation rates are calculated using the Schwartz-Slawsky-Herzfeld (SSH) and forced harmonic oscillator models for the vibrational energy transition probabilities in the temperature range 200 K-10 000 K. For inter-mode exchanges, using the SSH theory yields significantly underpredicted relaxation rates. The ranges of applicability for the LT formula and linearized theory are estimated; the original LT formula for inter-mode vibrational energy exchanges is not capable of accounting for the excitation of both vibrational modes; linearized models yield better results. Possible steps for improving the numerically efficient LT model are proposed. Published under license by AIP Publishing.

KW - MODELS

KW - DISSOCIATION

KW - FLOWS

KW - SIMULATION

KW - DIFFUSION

KW - MOLECULES

KW - KINETICS

KW - PLASMA

UR - http://www.scopus.com/inward/record.url?scp=85091634298&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/158764f8-7376-34e3-83ec-039296828d78/

U2 - 10.1063/5.0021654

DO - 10.1063/5.0021654

M3 - Article

VL - 32

JO - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 9

M1 - 096101

ER -