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.

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).

CARS (coherent anti-Stokes Raman scattering) investigations of the intermolecular vibrational energy transfer between nitrogen and carbon dioxide molecules

1993 ◽  
Vol 71 (3-4) ◽  
pp. 142-146 ◽  
Author(s):  
L. Wang ◽  
J. R. Xu ◽  
W. E. Jones
Keyword(s):  
Carbon Dioxide ◽  
Energy Transfer ◽  
Raman Scattering ◽  
Rate Constants ◽  
Transfer Rate ◽  
Vibrational Energy ◽  
Vibrational Energy Transfer ◽  
Scattering Technique ◽  
Anti Stokes ◽  
First Time

The CARS (coherent anti-Stokes Raman scattering) technique has been used for the first time to observe directly the vibrational energy transfer between nitrogen N2 (X1Σ, ν = 1, 2) and carbon dioxide. The transfer-rate constants were determined as (1.0 ± 0.1) × 1011 cm3 mol−1 s−1 and (1.7 ± 0.4) × 1011 cm3 mol−1 s−1 for N2(ν = 1) and N2(ν = 2), respectively.

SINGLET METHYLENE FROM THERMAL DECOMPOSITION OF DIAZOMETHANE. UNIMOLECULAR REACTIONS OF CHEMICALLY ACTIVATED CYCLOPROPANE AND DIMETHYLCYCLOPROPANE MOLECULES

1962 ◽  
Vol 40 (7) ◽  
pp. 1425-1451 ◽  
Author(s):  
D. W. Setser ◽  
B. S. Rabinovitch
Keyword(s):  
Thermal Decomposition ◽  
Rate Constants ◽  
Vibrational Energy ◽  
Kcal Mole ◽  
Thermal Systems ◽  
Geometric Isomerization ◽  
Wide Range ◽  
Structural Isomerization ◽  
Quantum Statistical ◽  
Singlet Methylene

The thermal decomposition of diazomethane (DM) into singlet methylene radicals and nitrogen has been studied from 225° to 450° in 10:1 olefin–diazomethane mixtures. At 2.5 cm pressure, k = 1.2 × 1012 exp (−34,000/RT) sec−1. The methylene radicals have similar reactivity to methylene generated from photolytic decomposition of DM, as judged by the follow-up reactions with ethylene and cis-butene-2. The structural isomerization reactions of energized cyclopropane and the structural and geometric isomerization of 1,2-dimethyl-cyclopropane (DMC), formed from the addition of the thermally generated methylene to the olefins, were measured from 250° to 450° over a wide range of pressures. For comparison, cyclopropane formed from photolysis at 4358 Å and 25° of DM and ethylene was studied. As judged from comparison of the experimental isomerization rate constants, the energy of the cyclopropanes formed at 350° in the thermal DM system is about the same as for cyclopropanes formed by photolysis at 4358 Å of DM at 25°. The experimental rate constants obtained on the assumption of strong collisions are compared with calculated rate constants which are based on quantum statistical models for kE which fit literature data on conventional thermal isomerization of cyclopropane and DMC. From this comparison, the average energies of the formed molecules in the thermal systems are estimated to be between 107 and 115 kcal/mole, depending upon the temperature. Photolysis at 25° of the ketene–ethylene system (3200 Å) and of DM–ethylene system (4358 Å) give cyclopropane characterized as being at 103 and 111 kcal/mole respectively. These energies deduced from kinetic data are compared with available thermochemical quantities; the existing value of ΔHf0(CH2N2) is questioned. Further support for fast intramolecular relaxation of vibrational energy in DMC, relative to the relaxation process for reaction, is noted. Comparison of data in the literature on the ketene and DM photolytic systems strongly suggests that a larger fraction of the excess light energy resides with methylene from ketene (0.65–0.8) than with methylene from DM (0.3–0.5). Various approximations for the calculation of kE are examined and are compared with accurate quantum statistical evaluation.

Kinetic Study of Vibrational Energy Transfer from a Wide Range of Vibrational Levels of O2(X3Σg−,v= 6−12) to CF4†

2008 ◽  
Vol 112 (39) ◽  
pp. 9290-9295 ◽  
Author(s):  
Shinji Watanabe ◽  
Hidekazu Fujii ◽  
Hiroshi Kohguchi ◽  
Takayuki Hatano ◽  
Ikuo Tokue ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Kinetic Study ◽  
Vibrational Energy ◽  
Vibrational Energy Transfer ◽  
Wide Range ◽  
Vibrational Levels

Effect of multiple encounters on vibrational to translational energy transfer

1994 ◽  
Vol 72 (3) ◽  
pp. 484-491 ◽  
Author(s):  
Neil Snider
Keyword(s):  
Energy Transfer ◽  
Vibrational Energy ◽  
Average Energy ◽  
Harmonic Oscillators ◽  
Relative Mass ◽  
Translational Energy ◽  
Fixed Temperature ◽  
Final Energy ◽  
Wide Range ◽  
Morse Oscillators

Vibrational to translational energy transfer was studied computationally and analytically for collinear, impulsive collisions with square well oscillators, harmonic oscillators, and Morse oscillators. At a fixed temperature T the average number of encounters is between one and two if the vibrational energy EV is large compared to kT and (or) if the relative mass of the collider is small. If these conditions are met, [Formula: see text] the average energy transferred per collision, varies nearly linearly with EV over a wide range. If the average number of encounters is greater than two, [Formula: see text] as a function of EV has a more complicated form. The average final energy, [Formula: see text] is less than what is predicted by the single encounter impulsive collision (SEI) model. Other things being equal, the ratio of the actual average final energy to the SEI average final energy is roughly the same for all of the above mentioned oscillators.

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