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

Low temperature rate coefficients of the H + CH+ → C+ + H2 reaction: New potential energy surface and time-independent quantum scattering

2015 ◽  
Vol 143 (11) ◽  
pp. 114304 ◽  
Author(s):  
Ghofran Werfelli ◽  
Philippe Halvick ◽  
Pascal Honvault ◽  
Boutheïna Kerkeni ◽  
Thierry Stoecklin
Keyword(s):  
Low Temperature ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Rate Coefficients ◽  
Quantum Scattering ◽  
Temperature Rate

Rotational de-excitations of C3H+ (1Σ+) by collision with He: new ab initio potential energy surface and scattering calculations

2020 ◽  
Vol 494 (4) ◽  
pp. 5675-5681 ◽  
Author(s):  
Sanchit Chhabra ◽  
T J Dhilip Kumar
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Cross Sections ◽  
Energy Surface ◽  
Molecular Ions ◽  
Basis Set ◽  
Rate Coefficients ◽  
Close Coupling ◽  
Collisional Rate Coefficients

ABSTRACT Molecular ions play an important role in the astrochemistry of interstellar and circumstellar media. C3H+ has been identified in the interstellar medium recently. A new potential energy surface of the C3H+–He van der Waals complex is computed using the ab initio explicitly correlated coupled cluster with the single, double and perturbative triple excitation [CCSD(T)-F12] method and the augmented correlation consistent polarized valence triple zeta (aug-cc-pVTZ) basis set. The potential presents a well of 174.6 cm−1 in linear geometry towards the H end. Calculations of pure rotational excitation cross-sections of C3H+ by He are carried out using the exact quantum mechanical close-coupling approach. Cross-sections for transitions among the rotational levels of C3H+ are computed for energies up to 600 cm−1. The cross-sections are used to obtain the collisional rate coefficients for temperatures T ≤ 100 K. Along with laboratory experiments, the results obtained in this work may be very useful for astrophysical applications to understand hydrocarbon chemistry.

A quasi-classical trajectory study of the reagent initial rotation quantum state effect on the reaction He + T2+ → HeT+ + T using an improved ab initio potential energy surface

2012 ◽  
Vol 90 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Ningjiu Zhao ◽  
Yufang Liu
Keyword(s):  
Angular Momentum ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Quantum Number ◽  
Relative Velocity ◽  
Energy Surface ◽  
Rotational Quantum Number ◽  
Chem Phys ◽  
Classical Trajectory ◽  
Positive Direction

In this work, we employed the quasi-classical trajectory (QCT) method to study the vector correlations and the influence of the reagent initial rotational quantum number j for the reaction He + T2+ (v = 0, j = 0–3) → HeT+ + T on a new potential energy surface (PES). The PES was improved by Aquilanti co-workers (Chem. Phys. Lett. 2009. 469: 26–30). The polarization-dependent differential cross sections (PDDCSs) and the distributions of P(θr), P([Formula: see text]r), and P(θr, [Formula: see text]r) are presented in this work. The plots of the PDDCSs provide us with abundant information about the distribution of the product angular momentum polarization. The P(θr) is used to describe the correlation between k (the relative velocity of the reagent) and j′ (the product rotational angular momentum). The distribution of dihedral angle P([Formula: see text]r) shows the k–k′–j′ (k′ refers to the relative velocity of the product) correlation. The PDDCS calculations illustrate that the product of this reaction is mainly backward scatter and it has the strongest polarization in the backward and sideways scattering directions. At the same time, the results of the P([Formula: see text]r) demonstrate that the product HeT+ tends to be oriented along the positive direction of the y axis and it tends to rotate right-handedly in planes parallel to the scattering plane. Moreover, the distribution of the P(θr) manifests that the product angular momentum is aligned along different directions relative to k. The direction of the product alignment may be perpendicular, opposite, or parallel to k. Moreover, our calculations are independent of the initial rotational quantum number.

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.

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