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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

The chemi-ionization (CI) processes in atom-Rydberg-atom collisions are investigated in this contribution. The rate coefficients for CI processes in $\textrm{Li}^{*}(n) + \textrm{Na}$, $\textrm{Li}^{*}(n) + \textrm{Li}$, $\textrm{Na}^{*}(n)…

Solar and Stellar Astrophysics · Physics 2018-12-04 Lj. M. Ignjatovic , V. A. Sreckovic , M. S. Dimitrijevic

The molecular anion C$_2^-$ has been of interest in the last few years as a candidate for laser cooling due to its electronic structure and favourable branching ratios to the ground electronic and vibrational state. Molecular hydrogen has…

The long range interaction between an antiprotonic helium atom $\bar{p}$He$^+$ and helium atom in its ground state is studied. We calculate the dispersion coefficients $C_6$ using the Complex Coordinate Rotation (CCR) formalism in order to…

Atomic Physics · Physics 2015-12-02 Vladimir I. Korobov , Zhen-Xiang Zhong , Quan-Long Tian

We report the measurement of collision rate coefficient for collisions between ultracold Cs atoms and low energy Cs+ ions. The experiments are performed in a hybrid trap consisting of a magneto-optical trap (MOT) for Cs atoms and a Paul…

Atomic Physics · Physics 2020-08-20 Sourav Dutta , S. A. Rangwala

The low-temperature (up to about 100K) collisional (de)excitation cross sections are computed using the full coupled-channel (CC) quantum dynamics for both Li$_2$ and Li$_2^+$ molecular targets in collision with $^4$He. The interaction…

Chemical Physics · Physics 2007-07-13 M. Wernli. E. Bodo , F. A. Gianturco

A detailed interpretation of the detected emission lines of environments in which propyne (or methyl acetylene, CH$_3$CCH) is observed requires a knowledge of its collisional rate coefficients with the most abundant species in the…

Astrophysics of Galaxies · Physics 2024-02-28 M. Ben Khalifa , B. Darna , J. Loreau

Utilizing a simplified quantum model approach, the low-energy inelastic collision processes between yttrium atoms (ions) and hydrogen atoms have been studied. Rate coefficients corresponding to the mutual neutralization, ion-pair formation,…

Solar and Stellar Astrophysics · Physics 2023-08-16 Yu Wang , Sofya Alexeeva , Feng Wang , Ling Liu , Yong Wu , JianGuo Wang , Gang Zhao , Svetlana A. Yakovleva , Andrey K. Belyaev

The energy dependence of the rates of the reactions between He$^+$ and ammonia (NY$_3$, Y= {H,D}), forming NY$_2^+$, Y and He as well as NY$^+$, Y$_2$ and He, and the corresponding product branching ratios have been measured at low…

The formation of anionic species in the interstellar medium from interaction of linear molecules containing carbon, nitrogen and hydrogen as atomic components (polyynes) with free electrons in the environment is modelled via a quantum…

Astrophysics of Galaxies · Physics 2015-06-05 F. Carelli , T. Grassi , F. Sebastianelli , F. A. Gianturco

For decades astronomers and astrophysicists believed that only positively charged ions were worthy of relevance in drawing the networks for possible chemical reactions in the interstellar medium, as well as in modeling the physical…

Chemical Physics · Physics 2012-09-14 Fabio Carelli

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

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

Using the ab initio computed Potential Energy Surface (PES) for the electronic interaction of the MgH$^+$ ($^1\Sigma$) ion with the He($^1$S) atom, we calculate the relevant state-changing rotationally inelastic collision cross sections…

Atomic Physics · Physics 2020-10-28 L. González-Sánchez , R. Wester , F. A. Gianturco

Using state-of-the-art ab initio interaction-induced dipole and potential-energy surfaces for hydrogen-helium (H2-He) pairs, we compute the rototranslational collision-induced absorption coefficient at 40-400 K for frequencies covering…

Earth and Planetary Astrophysics · Physics 2025-06-12 Glenn S. Orton , Magnus Gustafsson , Leigh N. Fletcher , Michael T. Roman , James A. Sinclair

We present comprehensive \textsl{ab initio} calculations of CO$_{\rm 2}$-H$_{\rm 2}$ and CO$_{\rm 2}$-He collisional properties from first principles, employing CCSD(T), potential calculations together with close-coupling dynamical…

We report energy levels, radiative rates (A-values) and lifetimes for the astrophysically-important Be-like ion C III. For the calculations, 166 levels belonging to the $n \le$ 5 configurations are considered and the {\sc grasp}…

Solar and Stellar Astrophysics · Physics 2015-06-24 K. M. Aggarwal , F. P. Keenan

In this paper we do three things. First, we outline the conditions under which the interaction rate of inelastic processes that change the internal state of a system of $N$ targets scales as $N^2$. This is an effect distinct from coherent…

High Energy Physics - Phenomenology · Physics 2024-11-06 Asimina Arvanitaki , Savas Dimopoulos , Marios Galanis

This study aims to reveal the important role and the respective rate rules of H atom abstractions by NO2 for better understanding NOX hydrocarbon interactions. To this end, H atom abstractions from C2 to C5 alkanes and alkenes 15 species by…

Chemical Physics · Physics 2024-08-28 Hongqing Wu , Ruoyue Tang , Xinrui Ren , Mingrui Wang , Guojie Liang , Haolong Li , Song Cheng

We present a theoretical study of rotationally elastic and inelastic collisions between molecular nitrogen ions and Rb atoms in the sub-Kelvin temperature regime prevalent in ion-atom hybrid trapping experiments. The cross sections for…