Theory of Gas Phase Scattering and Reactivity for Astrochemistry

Abstract

Great details may be found in many reviews (see e.g. [3][4][5][6]). Let us also underline that the chemistry of the ISM is relatively rich, with almost two hundred molecules detected, some of them quite unusual on the point of view of the laboratory: Long carbon chains, possibly chargedanions and cations-, and substituted (CH 3 , CN); some cyclic molecules (c−C 3 H 2 ), many radicals and protonated species, like the common HCO + , N 2 H + , H 2 O + and the all-important H + 3 . The precise identification of a chemical species (including all its isotopologues) is made possible from observed rotational/spectra from cm to FIR wavelengths and thanks to the fundamental spectroscopic experimental work which provide accurate frequencies to compare with. It makes use of large spectroscopic databases, still not precise enough especially so in the frequency region above 800-1000 GHz. Also, many isotopologues of the main molecules are detected, with D, 13 C, 15 N, 17 O, 18