Astrophysics/astrochemistry

Interestingly, the first in situ coupling of infrared detection with accelerated particles comes from astrophysics/astrochemistry studies... 

There has been particular interest in the chemistry of small organosilicon ions and their neutral counterparts for a number of reasons (i) Small SiCvHv molecules are well suited to draw analogies between the structural chemistry of silicon and carbon—or to state differences, (ii) The chemistry of small silicon compounds is viewed as fundamental in astrophysics and astrochemistry, and a large number of cationic and neutral SiRv molecules have been detected in interstellar and circumstellar matter. 

The astrochemistry of ions may be divided into topics of interstellar clouds, stellar atmospheres, planetary atmospheres and comets. There are many areas of astrophysics (stars, planetary nebulae, novae, supemovae) where highly ionized species are important, but beyond the scope of ion chemistry . (Still, molecules, including H2O, are observed in solar spectra [1551 and a surprise in the study of Supernova 1987A was the identification of molecular species, CO, SiO and possibly H [I56, 157]. ) In the early universe, after expansion... 

Quantum astrochemistry as an entire field in chemistry and astrophysics Quantum chemistry calculations thus constitute a natural complement, and sometimes a natural alternative, to experimental studies, to assign interstellar bands and lines (Figure... 

Cieariy, interactions from different fieids, astrochemistry, quantum chemistry, and laboratory spectroscopy, are essential to understand molecular astrophysics ... 

Kriegel et al 1987). Vibrational excitation of molecular ions is more efficient in collisions with buffer gas atoms or molecules heavier tlian helium (e.g. N2, Ar, etc.). This is demonstrated below. However, the occurrence of vibrational excitation is unfortvmate from the viewpoint of astrochemistry, since vibrational excitation of ions in drift tubes can obscure the influence of kinetic excitation on the rate coefficients of molecular ion-neutral reactions. Such information is needed in some astrophysical situations such as in interstellar MHD shocks. In these situations, the mean free times between collisions of the ions with the ambient gas are usually longer than the radiative lifetimes of the vibrational states of the ions and therefore the ions will generally be vibrationally relaxed. Thus data are required on the variation of the rate coefficients with Ej. for the reactions of ions in their ground vibrational state. So, drift tube data on molecular ion reactions must be applied with caution to astrophysical situations except that is for data obtained at low e/N where vibrational excitation of the molecular ions is minimal. 

Seme 50 years after the origins of astrochemistry, therefore, the conference was held at UHIST (September 1987) with the title "Eteactive rate coefficients in Astrophysics". Particular prominence was given to the 17 major invited reviews which were intended to cover the main areas of laboratory and theoretical chemistry and the astrochemical modelling. 

Astrophysics at QUB is supported by a grant from the Science and Technology Facilities Council (UK). EH acknowledges support for his research program in astrochemistry by the National Science Foundation (USA). 

D. Talbi, Theoretical approaches for studying astrochemistry, conferences of the chemistry in astrophysical media (astrohp), Ed. Pino, T Dartois, EPJ Web of Conferences, 2011.. 

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