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

Qizhen Hong,Andrea Lombardi,Fernando Pirani,Quanhua Sun,Cecilia Coletti,Massimiliano Bartolomei

doi:10.3390/molecules26237152

Abstract

Knowledge of energy exchange rate constants in inelastic collisions is critically required for accurate characterization and simulation of several processes in gaseous environments, including planetary atmospheres, plasma, combustion, etc. Determination of these rate constants requires accurate potential energy surfaces (PESs) that describe in detail the full interaction region space and the use of collision dynamics methods capable of including the most relevant quantum effects. In this work, we produce an extensive collection of vibration-to-vibration (V–V) and vibration-to-translation/rotation (V–T/R) energy transfer rate coefficients for collisions between CO and N molecules using a mixed quantum-classical method and a recently introduced (A. Lombardi, F. Pirani, M. Bartolomei, C. Coletti, and A. Laganà, Frontiers in chemistry, 7, 309 (2019)) analytical PES, critically revised to improve its performance against ab initio and experimental data of different sources. The present database gives a good agreement with available experimental values of V–V rate coefficients and covers an unprecedented number of transitions and a wide range of temperatures. Furthermore, this is the first database of V–T/R rate coefficients for the title collisions. These processes are shown to often be the most probable ones at high temperatures and/or for highly excited molecules, such conditions being relevant in the modeling of hypersonic flows, plasma, and aerospace applications.

Highlights

The kinetic modeling of gases is a relevant issue for the understanding and for the simulation of complex gaseous environments covering Earth and planetary atmospheres [1,2], combustion processes, plasma chemistry [3], and hypersonic aerodynamics [4,5], just to mention a few
For processes involving the transfer of vibrational energy quanta, the diatom vibrations in the quantum-classical method are described by solving the corresponding time-dependent Schrödinger equation, whereas for the remaining degrees of freedom the classical equations of motion are propagated under the influence of an effective potential, obtained as the quantum expectation value [7,8,9]
To the best of our knowledge, this is the first V–T/R rates database for collision between N2 (CO)-N2 collisions covering a wealth of excited states and temperatures

Summary

Introduction

The kinetic modeling of gases is a relevant issue for the understanding and for the simulation of complex gaseous environments covering Earth and planetary atmospheres [1,2], combustion processes, plasma chemistry [3], and hypersonic aerodynamics [4,5], just to mention a few. Because of the aforementioned difficulty in their determination, presently available repositories for combustion chemistry or astrochemical data contain structural and dynamical values which are often derived from simple extrapolations or oversimplified computations For this reason we believe that the accurate calculation of V–V and of the unprecedented V–T/R rates for a large variety of initial molecular vibrational states and a wide temperature range, carried out in an internally consistent way on the same potential energy surface, might represent a step forward in the kinetic modeling of a wealth of gaseous environments.

Potential Energy Surface

The Improved Lennard–Jones Formulation

Refinement of the PES over Experimental and Ab Initio Data

Results and Discussion

Conclusions