scholarly journals Breakdown of energy transfer gap laws revealed by full-dimensional quantum scattering between HF molecules

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Dongzheng Yang ◽  
Jing Huang ◽  
Xixi Hu ◽  
Hua Guo ◽  
Daiqian Xie
Keyword(s):  
Energy Transfer ◽  
Angular Momentum ◽  
Vibrational Energy ◽  
Energy Gap ◽  
Inelastic Collisions ◽  
Rate Coefficients ◽  
Quantum Scattering ◽  
Final States ◽  
Energy Gap Law ◽  
Quantitative Basis

Abstract Inelastic collisions involving molecular species are key to energy transfer in gaseous environments. They are commonly governed by an energy gap law, which dictates that transitions are dominated by those between initial and final states with roughly the same ro-vibrational energy. Transitions involving rotational inelasticity are often further constrained by the rotational angular momentum. Here, we demonstrate using full-dimensional quantum scattering on an ab initio based global potential energy surface (PES) that HF–HF inelastic collisions do not obey the energy and angular momentum gap laws. Detailed analyses attribute the failure of gap laws to the exceedingly strong intermolecular interaction. On the other hand, vibrational state-resolved rate coefficients are in good agreement with existing experimental results, validating the accuracy of the PES. These new and surprising results are expected to extend our understanding of energy transfer and provide a quantitative basis for numerical simulations of hydrogen fluoride chemical lasers.

scholarly journals The calculation of TV, VT, VV, VV' − rate coefficients for the collisions of the main atmospheric components

1998 ◽  
Vol 16 (7) ◽  
pp. 838-846 ◽  
Author(s):  
A. S. Kirillov
Keyword(s):  
Experimental Data ◽  
Energy Transfer ◽  
Vibrational Energy ◽  
Relaxation Times ◽  
Atmospheric Composition ◽  
Rate Coefficients ◽  
Frequency Change ◽  
Vibrational Energy Transfer ◽  
Ion Chemistry ◽  
Vibrationally Excited

Abstract. The first-order perturbation approximation is applied to calculate the rate coefficients of vibrational energy transfer in collisions involving vibrationally excited molecules in the absence of non-adiabatic transitions. The factors of molecular attraction, oscillator frequency change, anharmonicity, 3-dimensionality and quasiclassical motion have been taken into account in the approximation. The analytical expressions presented have been normalized on experimental data of VT-relaxation times in N2 and O2 to obtain the steric factors and the extent of repulsive exchange potentials in collisions N2-N2 and O2-O2. The approach was applied to calculate the rate coefficients of vibrational-vibrational energy transfer in the collisions N2-N2, O2-O2 and N2-O2. It is shown that there is good agreement between our calculations and experimental data for all cases of energy transfer considered.Key words. Ionosphere (Auroral ionosphere; ion chemistry and composition). Atmospheric composition and structure (Aciglow and aurora).

Rate coefficients for rotationally inelastic collisions of CO with H2

2001 ◽  
Vol 79 (2-3) ◽  
pp. 589-595 ◽  
Author(s):  
M Mengel ◽  
F C De Lucia ◽  
E Herbst
Keyword(s):  
Potential Energy ◽  
Energy Surface ◽  
Potential Surface ◽  
Chem Phys ◽  
Inelastic Collisions ◽  
Rate Coefficients ◽  
Quantum Scattering ◽  
Collision System ◽  
Pressure Broadening ◽  
Experimental Pressure

We have performed quantum-scattering calculations to determine inelastic rate coefficients of the astrophysically important collision system CO–H2. We have used a modified version of the most recent potential-energy surface by Jankowski and Szalewicz (J. Chem. Phys. 108, 3554 (1998)), which has been proven to be superior to a previous potential surface by comparison with experimental pressure broadening data. In contrast to previous studies we find that inelastic rates with Δ J = 2 for CO are smaller than those with Δ J = 1. PACS No.: 34.50Ez

An experimental exploration of the energy gap law for vibration-translation energy transfer: the iodine (I2*) + M system

1991 ◽  
Vol 95 (6) ◽  
pp. 2104-2107 ◽  
Author(s):  
Hong Du ◽  
Douglas J. Krajnovich ◽  
Charles S. Parmenter
Keyword(s):  
Energy Transfer ◽  
Energy Gap ◽  
Energy Gap Law

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

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7152
Author(s):  
Qizhen Hong ◽  
Massimiliano Bartolomei ◽  
Cecilia Coletti ◽  
Andrea Lombardi ◽  
Quanhua Sun ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rate Constants ◽  
Potential Energy Surfaces ◽  
Vibrational Energy ◽  
Classical Method ◽  
Rate Coefficients ◽  
Collision Dynamics ◽  
Aerospace Applications ◽  
Wide Range ◽  
Experimental Values

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 N2 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.

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