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In plasmas at very low temperatures formation of neutral atoms is dominated by collisional three-body recombination, owing to the strong ~ T^(-9/2) scaling of the corresponding recombination rate with the electron temperature T. While this…

Atomic Physics · Physics 2011-11-23 G. Bannasch , T. Pohl

First we present a recently developed 3D chemodynamical code for galaxy evolution from the K**2 collaboration. It follows the evolution of all components of a galaxy such as dark matter, stars, molecular clouds and diffuse interstellar…

Astrophysics · Physics 2009-11-10 R. Spurzem , P. Berczik , G. Hensler , Ch. Theis , P. Amaro-Seoane , M. Freitag , A. Just

We experimentally study the dynamics of a degenerate one-dimensional Bose gas that is subject to a continuous outcoupling of atoms. Although standard evaporative cooling is rendered ineffective by the absence of thermalizing collisions in…

The interest in the structure of ice-rich planetary bodies, in particular the differentiation between ice and rock, has grown due to the discovery of Kuiper belt objects and exoplanets. We thus carry out a parameter study for a range of…

Earth and Planetary Astrophysics · Physics 2022-03-30 Stephan Loveless , Dina Prialnik , Morris Podolak

Context. Evaporative (sublimation) cooling of icy interstellar grains occurs when the grains have been suddenly heated by a cosmic-ray (CR) particle or other process. It results in thermal desorption of icy species, affecting the chemical…

Astrophysics of Galaxies · Physics 2020-09-09 Juris Kalvāns , Juris Roberts Kalnin

Context: Chemical models of dense cloud cores often utilize the so-called pseudo-time-dependent approximation, in which the physical conditions are held fixed and uniform as the chemistry occurs. In this approximation, the initial…

Solar and Stellar Astrophysics · Physics 2015-05-18 G. E. Hassel , E. Herbst , E. A. Bergin

By improving the Bose-Einstein condensate model of dark matter through the repulsive three-particle interaction to better reproduce observables such as rotation curves, both different thermodynamic phases and few-particle correlations are…

Astrophysics of Galaxies · Physics 2022-11-22 A. M. Gavrilik , A. V. Nazarenko

The design, implementation, and performance of a customized carbon atom beam source for the purpose of investigating solid-state reaction routes in interstellar ices in molecular clouds are discussed. The source is integrated into an…

Solar and Stellar Astrophysics · Physics 2020-05-06 D. Qasim , M. J. A. Witlox , G. Fedoseev , K. -J. Chuang , T. Banu , S. A. Krasnokutski , S. Ioppolo , J. Kastner , E. F. van Dishoeck , H. Linnartz

An optical microtrap is realized on a dielectric surface by crossing a tightly focused laser beam with an horizontal evanescent-wave atom mirror. The nondissipative trap is loaded with $\sim$$10^5$ cesium atoms through elastic collisions…

Atomic Physics · Physics 2009-11-07 M. Hammes , D. Rychtarik , H. -C. Nägerl , R. Grimm

Processing by interstellar photons affects the composition of the icy mantles on interstellar grains. The rate of photodissociation in solids differs from that of molecules in the gas phase. The aim of this work was to determine an average,…

Astrophysics of Galaxies · Physics 2018-05-16 Juris Kalvans

In this work we investigate the effects of the environment on the X-ray photoelectron spectra of hydrogen chloride and the chloride ions adsorbed on ice surfaces, as well as of chloride ions in water droplets. In our approach, we combine a…

Chemical Physics · Physics 2023-09-18 Richard A. Opoku , Céline Toubin , André Severo Pereira Gomes

We discuss models that astrochemists have developed to study the chemical composition of the interstellar medium. These models aim at computing the evolution of the chemical composition of a mixture of gas and dust under as- trophysical…

Astrophysics of Galaxies · Physics 2013-10-01 Valentine Wakelam , Herma M. Cuppen , Eric Herbst

One of the major obstacles to accurately model the interstellar chemistry is an inadequate knowledge about the binding energy (BE) of interstellar species with dust grains. In denser region of molecular cloud, where very complex chemistry…

Astrophysics of Galaxies · Physics 2018-07-25 Ankan Das , Milan Sil , Prasanta Gorai , Sandip K. Chakrabarti , Jean-Christophe Loison

Context: Diffusion of species on the dust surface is a key process for determining the chemical composition of interstellar ices. On the dust surface, adsorbed species diffuse from one potential well to another and react with other adsorbed…

Astrophysics of Galaxies · Physics 2018-12-12 Wasim Iqbal , Valentine Wakelam , Pierre Gratier

The collapse of the primordial gas in the density regime $\sim 10^{8}\hbox{--}10^{10}$ cm$^{-3}$ is controlled by the three-body $\rm H_2$ formation process, in which the gas can cool faster than free-fall time $\hbox{--}$ a condition…

Astrophysics of Galaxies · Physics 2015-10-30 Jayanta Dutta

In cold core of dark molecular clouds, where the UV radiation from external sources is strongly attenuated, cosmic rays can induce chemical reactions on the surface of ice-covered grains promoting the ejection of the processed material to…

Deeply inside dense molecular clouds and protostellar disks, the interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions,…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 S. Pilling , E. Seperuelo Duarte , E. F. da Silveira , E. Balanzat , H. Rothard , A. Domaracka , P. Boduch

Photoevaporation is an important dispersal mechanism for protoplanetary disks. We conduct hydrodynamic simulations coupled with ray-tracing radiative transfer and consistent thermochemistry to study photoevaporative winds driven by…

Earth and Planetary Astrophysics · Physics 2017-09-20 Lile Wang , Jeremy J. Goodman

We present a detailed model for the thermal balance, chemistry, and radiative transfer within quiescent dense molecular cloud cores that contain a central protostar. Large variations in the gas temperature are expected to affect the…

Astrophysics · Physics 2009-10-30 S. D. Doty , D. A. Neufeld

We have investigated the thermally induced proton/deuteron exchange in mixed amorphous H$_2$O:D$_2$O ices by monitoring the change in intensity of characteristic vibrational bending modes of H$_2$O, HDO, and D$_2$O with time and as function…

Astrophysics of Galaxies · Physics 2015-06-23 Thanja Lamberts , Sergio Ioppolo , Herma Cuppen , Gleb Fedoseev , Harold Linnartz