Scientific article

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

Published inThe Journal of chemical physics, vol. 104, no. 5, p. 1979-1988
Publication date1996

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 + 2. On many points, the differences relative to the SiNH + 2 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 + 2. 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 + 2 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

  • Molecular ions
  • Dipole moments
  • Vibrational states
  • Self-
  • Consistent field
  • Electronic structure
  • Interstellar molecules
  • Silicon nitrides
  • Envelopes
  • Potential energy surfaces
Research group
Citation (ISO format)
PARISEL, Olivier, HANUS, Marc, ELLINGER, Yves. Interstellar silicon-nitrogen chemistry. III. The spectral signatures of the H2SiN+ molecular ion. In: The Journal of chemical physics, 1996, vol. 104, n° 5, p. 1979–1988. doi: 10.1063/1.470953
ISSN of the journal0021-9606

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