Toward detection of AlCH2 and AlCH2+ in the interstellar medium

Abstract

Highly reliable molecular properties have been computed for AlCH 2 and AlCH at the CCSD(T)/cc-pwCVQZ level of theory. These simple aluminum species are relevant to the chemistry of the interstellar medium (ISM) and circumstellar medium, and are proposed to form in regions where aluminum and methylene exist in appreciable concentrations because AlCH2 and AlCH are thermodynamically stable with respect to dissociation. Herein, dissociation energies were computed for both species through extrapolation to the complete basis set limit using focal point analysis. For the neutral species, 86 kcal mol-1 is required to heterolytically cleave the Al-C single bond, while the cationic species requires 38 kcal mol-1. To aid in identification within the ISM, the anharmonic (fundamental) frequencies, spectroscopic constants, and vibrationally averaged properties for AlCH2 and the corresponding cation are also reported. © 2013. The American Astronomical Society. All rights reserved.