Differential and integral cross sections for the inelastic scattering of NO (X 2Π) by Ar based on a new ab initio potential energy surface

1993 ◽  
Vol 99 (10) ◽  
pp. 7725-7738 ◽  
Author(s):  
Millard H. Alexander
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Inelastic Scattering ◽  
Ab Initio ◽  
Cross Sections ◽  
Energy Surface

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.

scholarly journals Ab initio potential-energy surface and rotationally inelastic integral cross sections of the Ar–CH4 complex

1997 ◽  
Vol 107 (3) ◽  
pp. 902-913 ◽  
Author(s):  
Tino G. A. Heijmen ◽  
Tatiana Korona ◽  
Robert Moszynski ◽  
Paul E. S. Wormer ◽  
Ad van der Avoird
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Cross Sections ◽  
Energy Surface

scholarly journals The hyperfine excitation of OH radicals by He

2016 ◽  
Vol 70 (4) ◽  
Author(s):  
Sarantos Marinakis ◽  
Yulia Kalugina ◽  
François Lique
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Cross Sections ◽  
Nuclear Spin ◽  
Energy Surface ◽  
Quantum Scattering ◽  
Oh Radicals ◽  
Vibrational Motion ◽  
Astronomical Observations

Abstract Hyperfine-resolved collisions between OH radicals and He atoms are investigated using quantum scattering calculations and the most recent ab initio potential energy surface, which explicitly takes into account the OH vibrational motion. Such collisions play an important role in astrophysics, in particular in the modelling of OH masers. The hyperfine-resolved collision cross sections are calculated for collision energies up to 2500 cm-1 from the nuclear spin free scattering S-matrices using a recoupling technique. The collisional hyperfine propensities observed are discussed. As expected, the results from our work suggest that there is a propensity for collisions with ΔF = Δj. The new OH−He hyperfine cross sections are expected to significantly help in the modelling of OH masers from current and future astronomical observations. Graphical abstract

Collisional excitation of interstellar PO(X2Π) by He: new ab initio potential energy surfaces and scattering calculations

2018 ◽  
Vol 20 (8) ◽  
pp. 5407-5414 ◽  
Author(s):  
François Lique ◽  
Izaskun Jiménez-Serra ◽  
Serena Viti ◽  
Sarantos Marinakis
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Inelastic Scattering ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Quantum Scattering ◽  
Collisional Excitation ◽  
Energy Surfaces

The inelastic scattering of PO (X, v = 0) has been investigated by quantum scattering calculations using a new potential energy surface.

Semiclassical study of sudden approximations for rotationally inelastic scattering of Ar + HF

1994 ◽  
Vol 72 (3) ◽  
pp. 985-994 ◽  
Author(s):  
James J. C. Barrett ◽  
Howard R. Mayne ◽  
Mark Keil ◽  
Leslie J. Rawluk
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Inelastic Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Infinite Order ◽  
Energy Surface ◽  
Differential Cross Sections ◽  
Sudden Approximation ◽  
Rotationally Inelastic Scattering

"Exact" quantum close coupled (CC) and infinite-order sudden approximation (IOSA) calculations have been carried out for the Ar + HF system on an accurate potential energy surface. The differential cross sections from the IOSA calculations show marked differences from the CC results. We find that the energy sudden component of the IOSA breaks down in a different manner for small and large impact parameters, significantly shifting and distorting the state-to-state differential cross sections. We also find that the centrifugal sudden approximation alone reproduces all features of the full semiclassical calculations quite faithfully. Through the use of several rotational sudden approximations, including a semiclassical version of the IOSA, we identify how the differences between the CC and IOSA results arise.

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