UNIGE document Scientific Article
previous document  unige:2968  next document
add to browser collection

Interstellar silicon-nitrogen chemistry. III. The spectral signatures of the H2SiN+ molecular ion

Hanus, Marc
Published in Journal of Chemical Physics. 1996, vol. 104, no. 5, p. 1979-1988
Abstract The recent detection of SiN in the outer envelope of the IRC+10216 carbon star has renewed the interest for the gas phase interstellar silicon chemistry. In this contribution, we present a theoretical study of the H2SiN+ molecular ion, the silicon hydrogenated counterpart of the previously studied SiNH<sup> + </sup><sub>2</sub>. On many points, the differences relative to the SiNH<sup> + </sup><sub>2</sub> isomer have been found to be dramatic. As an example, the dipole moment is computed to be 3.8 D while being only 0.5 D in SiNH<sup> + </sup><sub>2</sub>. The radio, infrared and electronic signatures have been evaluated at a quantitative level. The rotational constants and vibrational frequencies have been determined using Möller–Plesset MPn (n=2,3,4), coupled cluster (CCSDT) and complete active space self-consistent field (CASSCF) methods for H2SiN+ and some of its isotopomers. These quantities have been corrected using a scaling procedure derived from previous studies on the HNSi, HSiN, HSiNH2, H2SiNH, and SiNH<sup> + </sup><sub>2</sub> species in order to provide quantitative results. The failure of single-reference perturbation theories to predict a relevant infrared spectrum is discussed. Intense bands around 550, 950, and 2300 cm–1 are predicted. The electronic spectrum has been obtained using a coupled multiconfiguration SCF–perturbation treatment (MC/P): It is characterized by a large number of excited states, none of them having a strong transition moment. The lowest excited state is predicted to lie 0.54 eV above the ground state, but the first allowed transition having a nonnegligible oscillator strength has to be searched at 6.44 eV
Keywords Molecular ionsDipole momentsVibrational statesSelf-Consistent fieldElectronic structureInterstellar moleculesSilicon nitridesEnvelopesPotential energy surfaces
Full text
This document has no fulltext available yet, but you can contact its author by using the form below.
Research group Groupe Weber
(ISO format)
PARISEL, Olivier, HANUS, Marc, ELLINGER, Yves. Interstellar silicon-nitrogen chemistry. III. The spectral signatures of the H2SiN+ molecular ion. In: Journal of Chemical Physics, 1996, vol. 104, n° 5, p. 1979-1988. https://archive-ouverte.unige.ch/unige:2968

202 hits

0 download


Deposited on : 2009-09-21

Export document
Format :
Citation style :