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Rate coefficients for rotational transitions in H_2 induced by H_2 impact are presented. Extensive quantum mechanical coupled-channel calculations based on a recently published (H_2)_2 potential energy surface were performed. The potential…

Rate coefficients for state-to-state rotational transitions in CO induced by both para- and ortho-H$_2$ collisions are presented. The results were obtained using the close-coupling method and the coupled-states approximation, with the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Benhui Yang , P. C. Stancil , N. Balakrishnan , R. C. Forrey

Rotational transitions in molecular hydrogen collisions are computed. The two most recently developed potential energy surfaces for the H2-H2 system are used from the following works: 1) A.I. Boothroyd, P.G. Martin, W.J. Keogh, M.J.…

Chemical Physics · Physics 2009-11-11 Renat A. Sultanov , Dennis Guster

New quantum scattering calculations for rotational deexcitation transitions of CO induced by H collisions using two CO-H potential energy surfaces (PESs) from Shepler et al. (2007) are reported. State-to-state rate coefficients are computed…

Solar and Stellar Astrophysics · Physics 2015-06-15 Benhui Yang , P. C. Stancil , N. Balakrishnan , R. C. Forrey , J. M. Bowman

We compute the rotational quenching rates of the first 81 rotational levels of ortho- and para-H2CO in collision with ortho- and para-H2, for a temperature range of 10-300 K. We make use of the quantum close-coupling and coupled-states…

Solar and Stellar Astrophysics · Physics 2015-06-15 Laurent Wiesenfeld , Alexandre Faure

Theoretical rotational quenching cross sections and rate coefficients of ortho- and para-H$_2$O due to collisions with He atoms are presented. The complete angular momentum close-coupling approach as well as the coupled-states approximation…

Solar and Stellar Astrophysics · Physics 2015-06-15 Benhui Yang , M. Nagao , W. Satomi , M. Kimura , P. C. Stancil

The interpretation of water line emission from existing observations and future HIFI/Herschel data requires a detailed knowledge of collisional rate coefficients. Among all relevant collisional mechanisms, the rotational (de)excitation of…

Astrophysics · Physics 2009-11-13 A. Faure , N. Crimier , C. Ceccarelli , P. Valiron , L. Wiesenfeld , M. -L. Dubernet

We present the first accurate rate coefficients for the rotational excitation of CO by H2O in the kinetic temperature range 5-100 K. The statistical adiabatic channel method (SACM) is combined with a high-level rigid-rotor CO-H2O…

Earth and Planetary Astrophysics · Physics 2020-02-13 A. Faure , F. Lique , J. Loreau

State-selected total cross sections and thermal rate coefficients are computed for the HD + $ortho$-/$para$-H$_2$ rotational energy transfer collision at low temperatures: 2 K $\lesssim$ T $\lesssim$ 300 K. A modified H$_2$-H$_2$ potential…

Chemical Physics · Physics 2016-01-28 Renat A. Sultanov , Dennis Guster , S. K. Adhikari

We present quantum dynamical calculations that describe the rotational excitation of H$_2$O due to collisions with H atoms. We used a recent, high accuracy potential energy surface, and solved the collisional dynamics with the…

Astrophysics of Galaxies · Physics 2015-06-23 F. Daniel , A. Faure , P. J. Dagdigian , M. -L. Dubernet , F. lique , G. Pineau des forêts

Carbon monoxide is a simple molecule present in many astrophysical environments, and collisional excitation rate coefficients due to the dominant collision partners are necessary to accurately predict spectral line intensities and extract…

Astrophysics of Galaxies · Physics 2015-11-17 Kyle M. Walker , L. Song , B. H. Yang , G. C. Groenenboom , A. van der Avoird , N. Balakrishnan , R. C. Forrey , P. C. Stancil

We present quantum mechanical and quasiclassical trajectory calculations of cross sections for rovibrational transitions in ortho- and para-H_2 induced by collisions with He atoms. Cross sections were obtained for kinetic energies between…

Astrophysics · Physics 2007-05-23 N. Balakrishnan , M. Vieira , J. F. Babb , R. C. Forrey , A. Dalgarno , S. Lepp

OH is a cornerstone molecule in the chemistry of interstellar and circumstellar media and is ubiquitously detected in warm gas thanks to its infrared rotational lines. However, the excitation processes of OH remain poorly characterized. We…

The hydronium cation plays a crucial role in interstellar oxygen and water chemistry. While its spectroscopy was extensively investigated earlier, the collisional excitation of H$_3$O$^+$ is not well studied yet. In this work we present…

Chemical Physics · Physics 2022-11-07 S. Demes , François Lique , Alexandre Faure , Floris van der Tak , Claire Rist , Pierre Hily-Blant

Results for quantum mechanical calculations of the integral cross sections and corresponding thermal rate coefficients for para-/ortho-H2+HD collisions are presented. Because of significant astrophysical interest in regard to the cooling of…

Chemical Physics · Physics 2015-05-13 Renat A. Sultanov , Avas V. Khugaev , Dennis Guster

Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations…

Solar and Stellar Astrophysics · Physics 2015-06-10 Benhui Yang , K. M. Walker , R. C. Forrey , P. C. Stancil , N. Balakrishnan

Modeling environments that are not in local thermal equilibrium, such as protoplanetary disks or planetary atmospheres, with molecular spectroscopic data from space telescopes requires knowledge of the rate coefficients of rovibrationally…

Atomic Physics · Physics 2023-10-10 Taha Selim , Ad van der Avoird , Gerrit C. Groenenboom

The availability of collisional rate coefficients with H$_2$ is a pre-requisite for interpretation of observations of molecules whose energy levels are populated under non local thermodynamical equilibrium conditions. In the current study,…

Astrophysics of Galaxies · Physics 2015-06-22 F. Daniel , A. Faure , L. Wiesenfeld , E. Roueff , D. C. Lis , P. Hily-Blant

Quantum-mechanical close-coupling calculations for state-to-state cross sections and thermal rates are reported for H2+H2 collisions. Two recently developed potential energy surfaces (PES) for the H2-H2 system are applied, namely, the…

Chemical Physics · Physics 2009-11-11 Renat A. Sultanov , Dennis Guster

Aim: We present an improved database of temperature dependent rate coefficients for rotational state-to-state transitions in H$_{2}$O + H$_{2}$O collisions. The database includes 231 transitions between the lower $para$- and 210 transitions…

Chemical Physics · Physics 2023-10-19 Bikramaditya Mandal , Dmitri Babikov
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