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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

Cross sections for the rotational (de)excitation of CO by ground state para- and ortho-H_2 are obtained using quantum scattering calculations for collision energies between 1 and 520 cm^{-1}. A new CO-H_2 potential energy surface is…

Astrophysics · Physics 2008-11-26 M. Wernli , P. Valiron , A. Faure , L. Wiesenfeld , P. Jankowski , K. Szalewicz

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 have studied the fundamental rotational relaxation and excitation collision of OH- J=0 <-> 1 with helium at different collision energies. Using state-selected photodetachment in a cryogenic ion trap, the collisional excitation of the…

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

Context. In dffuse interstellar clouds the excitation temperature derived from the lowest levels of H$^+_3$ is systematically lower than that derived from H2. The differences may be attributed to the lack of state-specific formation and…

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…

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

Modeling of molecular emission from interstellar clouds requires the calculation of rates for excitation by collisions with the most abundant species. The present paper focuses on the calculation of rate coefficients for rotational…

Astrophysics of Galaxies · Physics 2015-05-18 E. Sarrasin , D. Ben Abdallah , M. Wernli , A. Faure , J. Cernicharo , F. Lique

The dynamics of the reaction H + OH $\to$ O (3P) + H2 have been studied in a series of quasi-classical trajectory (QCT) calculations and transition state theory (TST) methods using high quality 3A' and 3A'' potential energy surfaces (PESs).…

Solar and Stellar Astrophysics · Physics 2014-02-27 Xiaohu Li , Carina Arasa , Marc C. van Hemert , Ewine F. van Dishoeck

State-to-state differential cross sections (DCSs) for rotationally inelastic scattering of H2O by H2 have been measured at 71.2 meV (574 cm-1) and 44.8 meV (361 cm-1) collision energy using crossed molecular beams combined with velocity map…

Chemical Physics · Physics 2015-05-27 C-H. Yang , G. Sarma , D. H. Parker , J. J ter Meulen , L. Wiesenfeld

The Diep and Johnson (DJ) H$_2$-H$_2$ potential energy surface (PES) obtained from the first principles [P. Diep, K. Johnson, J. Chem. Phys. 113, 3480 (2000); 114, 222 (2000)], has been adjusted through appropriate rotation of the…

Chemical Physics · Physics 2015-03-19 Renat A. Sultanov , Dennis Guster , S. K. Adhikari

A close coupling quantum-mechanical calculation is performed for rotational energy transfer in a HD+HD collision at very low energy, down to the ultracold temperatures: $T \sim 10^{-8}$ K. A global six-dimensional H$_2$-H$_2$ potential…

Chemical Physics · Physics 2015-06-03 Renat A. Sultanov , Dennis Guster , S. K. Adhikari

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

We present calculated rate coefficients for ro-vibrational transitions of CO in collisions with H atoms for a gas temperature range of 10 K $\leq T \leq$ 3000 K, based on the recent three-dimensional ab initio H-CO interaction potential of…

Astrophysics of Galaxies · Physics 2015-11-23 L. Song , N. Balakrishnan , K. M. Walker , P. C. Stancil , W. F. Thi , I. Kamp , A. van der Avoird , G. C. Groenenboom

We employ an accurate, ab initio potential energy surface (PES) which describes the electronic interaction energy between the molecular anion OH$^-$ ($^1\Sigma^+$) and the neutral rubidium atom Rb ($^2S$), to evaluate the elastic and…

Atomic Physics · Physics 2018-07-31 L. González-Sánchez , F. Carelli , F. A. Gianturco , R. Wester

We aim to obtain accurate rate coefficients for the collisional excitation of CH+ by He for high gas temperatures. The ab initio coupled-cluster [CCSD(T)] approximation was used to compute the interaction potential energy. Cross sections…

Solar and Stellar Astrophysics · Physics 2015-05-14 K. Hammami , L. C. Owono Owono , P. Staeuber

A series of Multichannel Quantum Defect Theory-based computations have been performed, in order to produce the cross sections of rotational transitions (excitations $N_{i}^{+}-2 \rightarrow$ $N_{i}^{+}$, de-excitations $N_{i}^{+}$…

Instrumentation and Methods for Astrophysics · Physics 2024-05-13 O. Motapon , N. Pop , F. Argoubi , J. Zs. Mezei , M. D. Epée Epée , A. Faure , M. Telmini , J. Tennyson , I. F. Schneider

A new database of collisional rate coefficients for transitions between the rotational states of H$_2$O collided with H$_2$ background gas is developed. The goal is to expand over the other existing databases in terms of the rotational…

Quantum Physics · Physics 2024-12-18 Carolin Joy , Dulat Bostan , Bikramaditya Mandal , Dmitri Babikov

We present quantum mechanical close-coupling calculations of collisions between two hydrogen molecules over a wide range of energies, extending from the ultracold limit to the super-thermal region. The two most recently published potential…

Atomic Physics · Physics 2009-11-13 Teck-Ghee Lee , N. Balakrishnan , R. C. Forrey , P. C. Stancil , D. R. Schultz , Gary J. Ferland
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