Related papers: Reaction Networks For Interstellar Chemical Modell…
Because of new telescopes that will dramatically improve our knowledge of the interstellar medium, chemical models will have to be used to simulate the chemistry of many regions with diverse properties. To make these models more robust, it…
Gas-phase processes were long thought to be the key formation mechanisms for complex organic molecules in star-forming regions. However, recent experimental and theoretical evidence has cast doubt on the efficiency of such processes.…
One of the stumbling blocks for studying the evolution of interstellar molecules is the lack of adequate knowledge of the rate co-efficients of various reactions which take place in the Interstellar medium and molecular clouds. Some of the…
Recent observations have revealed significant variations in the abundances of gas- and ice-phase molecules in galaxies with different luminosities and types. In order to discuss the physical origins of these variations, we incorporate gas-…
The gas-phase chemistry of dark clouds has been studied with a treatment of uncertainties caused both by errors in individual rate coefficients and uncertainties in physical conditions. Moreover, a sensitivity analysis has been employed to…
AIM: We have recently developed a microscopic Monte Carlo approach to study surface chemistry on interstellar grains and the morphology of ice mantles. The method is designed to eliminate the problems inherent in the rate-equation formalism…
Astrochemical models are essential to bridge the gap between the timescales of reactions, experiments, and observations. Ice chemistry in these models experiences a large computational complexity as a result of the many parameters required…
The observed gas-phase molecular inventory of hot cores is believed to be significantly impacted by the products of chemistry in interstellar ices. In this study, we report the construction of a full macroscopic Monte Carlo model of both…
Chemical models used to study the chemical composition of the gas and the ices in the interstellar medium are based on a network of chemical reactions and associated rate coefficients. These reactions and rate coefficients are partially…
A new chemical model is presented for the carbon-rich circumstellar envelope of the AGB star IRC+10216. The model includes shells of matter with densities that are enhanced relative to the surrounding circumstellar medium. The chemical…
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…
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…
The physical conditions in a collapsing cloud can be traced by observations of molecular lines. To correctly interpret these observations the abundance distributions of the observed species need to be derived. The chemistry in a collapsing…
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…
HNC and HCN, typically used as dense gas tracers in molecular clouds, are a pair of isomers that have great potential as a temperature probe because of temperature dependent, isomer-specific formation and destruction pathways. Previous…
Dust grains are an important component of the interstellar medium (ISM) of galaxies. We present the first direct measurement of the residence times of interstellar dust in the different ISM phases, and of the transition rates between these…
We review the reactions involving HCN and HNC in dark molecular clouds to elucidate new chemical sources and sinks of these isomers. We find that the most important reactions for the HCN-HNC system are Dissociative Recombination (DR)…
Theoretical studies have revealed that dust grains are usually moving fast through the turbulent interstellar gas, which could have significant effects upon interstellar chemistry by modifying grain accretion. This effect is investigated in…
Ice is ubiquitous in the interstellar medium. We model the formation of the main constituents of interstellar ices, including H2O, CO2 , CO, and CH3 OH. We strive to understand what physical or chemical parameters influence the final…
Chemical models have been developed over the years by astrophysicists to study the pro- cesses at play in the various environments of the interstellar medium (ISM) that define the chemical composition of the gas and the dust. These…