Related papers: Laboratory Synthesis of Molecular Hydrogen on Surf…
Recent experimental results on the formation of molecular hydrogen on astrophysically relevant surfaces under conditions similar to those encountered in the interstellar medium provided useful quantitative information about these processes.…
A knowledge of the recombination time on the grain surfaces has been a major obstacle in deciding the production rate of molecular hydrogen and other molecules in the interstellar medium. We present a numerical study to compute this time…
Recent experimental results about the formation of molecular hydrogen on astrophysically relevant surfaces under conditions close to those encountered in the interstellar medium are analyzed using rate equations. The parameters of the rate…
In the interstellar clouds, molecular hydrogens are formed from atomic hydrogen on grain surfaces. An atomic hydrogen hops around till it finds another one with which it combines. This necessarily implies that the average recombination…
We report on laboratory measurements of molecular hydrogen formation and recombination on an olivine slab as a function of surface temperature under conditions relevant to those encountered in the interstellar medium. On the basis of our…
Molecular beam experiments that use low-temperature bolometers as (energy-) detectors are well suited to the study of physisorption and recombination of hydrogen on low-temperature surfaces. Experiments where this technique is combined with…
A prominent chemical reaction in interstellar clouds is the formation of molecular hydrogen by recombination, which essentially takes place on dust grain surfaces. Analytical approaches to model such a system have hitherto neglected the…
The recombination of hydrogen in the interstellar medium, taking place on surfaces of microscopic dust grains, is an essential process in the evolution of chemical complexity in interstellar clouds. The H_2 formation process has been…
Hydrogen recombination is one of the most important atomic processes in many astrophysical objects such as Type II supernova (SN~II) atmospheres, the high redshift universe during the cosmological recombination era, and H II regions in the…
Astrophysical models of primordial star formation require rate constants for three-body recombination as input. The current status of these rates for H2 due to collisions with H is far from satisfactory, with published rate constants…
Molecular hydrogen has an important role in the early stages of star formation as well as in the production of many other molecules that have been detected in the interstellar medium. In this review we show that it is now possible to study…
We investigate how the existence of hydrogen molecules on grain surfaces may affect H$_2$ formation efficiency in diffuse and translucent clouds. Hydrogen molecules are able to reduce the desorption energy of H atoms on grain surfaces in…
We present the first systematic measurement of the binding energy $E_a$ of hydrogen atoms to the surface of saturated $^3$He-$^4$He mixture films. $E_a$ is found to decrease almost linearly from 1.14(1) K down to 0.39(1) K, when the…
The basic approach for measuring electron-ion recombination rate coefficients in merged-beams electron-ion collision experiments at heavy-ion storage rings is outlined. As an example experimental results for the low temperature…
The study of the formation of molecular hydrogen on low temperature surfaces is of interest both because it allows to explore elementary steps in the heterogeneous catalysis of a simple molecule and because of the applications in…
Experimental results on the formation of molecular hydrogen on amorphous silicate surfaces are presented for the first time and analyzed using a rate equation model. The energy barriers for the relevant diffusion and desorption processes…
The advent of precise measurements of the cosmic microwave background (CMB) anisotropies has motivated correspondingly precise calculations of the cosmic recombination history. Cosmic recombination proceeds far out of equilibrium because of…
We study the evolution of molecular hydrogen on the grain surfaces and in the gas phase using both the rate equation (which tracks the average number of molecules) and the master equation (which tracks the expectation values of molecules).…
Hydrogen recombination in the early Universe in the presence of a magnetic field is studied. An equation for the temperature of recombination in the presence of a magnetic field is derived. Limiting cases of weak and strong fields are…
We study molecular hydrogen formation in and on solids. We construct a model with surface sites and bulk sites capable of describing (1) the motion and exchange of H and H_2 between surface and bulk, (2) the recombination of H and…