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Interpretations of the very rich second solar spectrum of the MgH molecule face serious problems owing to the complete lack of any information about rates of collisions between the MgH and hydrogen atoms. This work seeks to begin the…

Solar and Stellar Astrophysics · Physics 2021-07-27 Saleh Qutub , Yulia Kalugina , Moncef Derouich

The behaviour of molecules in space is to a large extent governed by where they freeze out or sublimate. The molecular binding energy is thus an important parameter for many astrochemical studies. This parameter is usually determined with…

Astrophysics of Galaxies · Physics 2022-10-05 Torben Villadsen , Niels F. W. Ligterink , Mie Andersen

Intermolecular hydrogen transfer free radical reactions are common in the combustion process and in a number of organic chemistry reactions. Therefore, evaluating the pressure and temperature-dependent rate constants of them is of great…

Chemical Physics · Physics 2024-04-01 Yi Sun

The energy to desorb atomic oxygen from an interstellar dust grain surface, $E_{\rm des}$, is an important controlling parameter in gas-grain models; its value impacts the temperature range over which oxygen resides on a dust grain.…

Astrophysics of Galaxies · Physics 2015-06-23 Jiao He , Jianming Shi , Tyler Hopkins , Gianfranco Vidali , Michael J. Kaufman

The hydrogenation of polycyclic aromatic hydrocarbons (PAHs) is crucial to understanding molecular hydrogenation formation in the interstellar medium. This process also helps to elucidate the weakening of the aromatic bonds in PAHs, which…

Astrophysics of Galaxies · Physics 2025-09-03 S. Haid , K. Gugeler , J. Kästner , D. Campisi

We investigated the behavior of H$_2$, main constituent of the gas phase in dense clouds, after collision with amorphous solid water (ASW) surfaces, one of the most abundant chemical species of interstellar ices. We developed a general…

Chemical Physics · Physics 2020-03-20 G. Molpeceres , J. Kästner

Charge-exchange reactions between outflowing stellar wind protons and interstellar neutral hydrogen atoms entering a stellar astrosphere produce a region of piled-up-decelerated neutral hydrogen called the hydrogen wall. Absorption by this…

Solar and Stellar Astrophysics · Physics 2014-08-27 Jeffrey L. Linsky , Brian E. Wood

Resonant formation of the muonic molecule dt-mu in t-mu atom collision with condensed H/D/T targets is considered. A specific resonance correlation function, which is a generalization of the Van Hove single-particle correlation function, is…

Atomic Physics · Physics 2018-03-09 Andrzej Adamczak , Mark Faifman

Major components of ices on interstellar grains in molecular clouds - water and carbon oxides - occur at various optical depths. This implies that selective desorption mechanisms are at work. An astrochemical model of a contracting low-mass…

Astrophysics of Galaxies · Physics 2015-06-23 Juris Kalvans

We study the rotational and vibrational heating of diatomic molecules placed near a surface at finite temperature on the basis of macroscopic quantum electrodynamics. The internal molecular evolution is governed by transition rates that…

Quantum Physics · Physics 2009-12-14 Stefan Yoshi Buhmann , M. R. Tarbutt , Stefan Scheel , E. A. Hinds

We use a density functional approach to calculate the contact angle of the water model on a heterogeneous, graphite-like surface. The surface heterogeneity results from the pre-adsorption of a layer of spherical species. The pre-adsorbed…

Soft Condensed Matter · Physics 2022-10-04 K. Dąbrowska , O. Pizio , S. Sokołowski

The evolution of star-forming regions and their thermal balance are strongly influenced by their chemical composition, that, in turn, is determined by the physico-chemical processes that govern the transition between the gas phase and the…

The properties of inhomogeneous neutron matter are crucial to the physics of neutron-rich nuclei and the crust of neutron stars. Advances in computational techniques now allow us to accurately determine the binding energies and densities of…

Nuclear Theory · Physics 2011-02-01 S. Gandolfi , J. Carlson , Steven C. Pieper

In this paper, we study heliospheric Ly-$\alpha$ absorption toward nearby stars in different lines of sight. We use the Baranov-Malama model of the solar wind interaction with a two-component (charged component and H atoms) interstellar…

Astrophysics · Physics 2015-06-24 V. Izmodenov , B. Wood , R. Lallement

When hydrogen molecules collide with a surface, they can either scatter away from the surface or stick to the surface through a dissociation reaction which leaves two H atoms adsorbed on the surface. The relative probabilities of these two…

Chemical Physics · Physics 2024-10-03 H. Chadwick , G. Zhang , C. J. Baker , P. L. Smith , G. Alexandrowicz

We describe experiments where 2D atomic hydrogen gas is compressed thermally at a small "cold spot" on the surface of superfluid helium and detected directly with electron-spin resonance. We reach surface densities up to 5e12 1/cm^2 at…

Soft Condensed Matter · Physics 2009-11-10 S. Vasilyev , J. Jarvinen , A. I. Safonov , S. Jaakkola

With the Cosmic Origins Spectrograph onboard the Hubble Space Telescope, we have detected molecular hydrogen in the atmospheres of three white dwarfs with effective temperatures below 14,000 K, G29-38, GD 133 and GD 31. This discovery…

Solar and Stellar Astrophysics · Physics 2015-06-15 S. Xu , M. Jura , D. Koester , B. Klein , B. Zuckerman

Gas in galactic disks is collected by gravitational instabilities into giant atomic-molecular complexes, but only the inner, molecular parts of these structures are able to collapse to form stars. Determining what controls the ratio of…

Astrophysics · Physics 2009-11-13 Mark R. Krumholz , Christopher F. McKee , Jason Tumlinson

Surface chemistry on interstellar dust grains is recognized as a central component in astrochemical models, representing a plausible formation route for many of the observed complex molecular species. However, key parameters governing…

Astrophysics of Galaxies · Physics 2026-01-22 Francesco Benedetti , Mauro Satta , Tommaso Grassi , Stefan Vogt-Geisse , Stefano Bovino

The presence of small amounts of atomic hydrogen, detected as absorption dips in the 21 cm line spectrum, is a well-known characteristic of dark clouds. The abundance of hydrogen atoms measured in the densest regions of molecular clouds can…

Astrophysics of Galaxies · Physics 2018-11-21 Marco Padovani , Daniele Galli , Alexei V. Ivlev , Paola Caselli , Andrea Ferrara