High Resolution Study of the &ngr;₂, 2&ngr;₁, &ngr;₁+ &ngr;₃, and 2&ngr;₃Bands of Hydrogen Telluride: Determination of Equilibrium Rotational Constants and Structure

Author： Flaud J.M. Arcas P. Bürger H. Polanz O. Halonen L.

Publisher： Academic Press

ISSN： 0022-2852

Source： Journal of Molecular Spectroscopy, Vol.183, Iss.2, 1997-06, pp. : 310-335

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Abstract

High resolution Fourier transform spectra of a natural and a¹³⁰Te monoisotopic sample of H₂Te have been recorded at a resolution of 0.0022 cm^-1in the 11.6 μm spectral region, as well as a spectrum of a natural sample of H₂Te at a resolution of 0.0051 cm^-1in the 2.4 μm region. In the 11.6 μm region the main absorbing band is the &ngr;₂band, the analysis of which was rather easy. On the other hand, in the 2.4 μm region three bands are absorbing, namely 2&ngr;₁, &ngr;₁+ &ngr;₃, and 2&ngr;₃, the last being much weaker than the others. The analysis in this spectral domain was much more difficult because of resonances. Indeed it proved not possible to reproduce the observed lines without taking into account the Darling–Dennison interaction between the levels of the (200) and (002) states and the Coriolis interactions between the levels of (200) and (101) and between those of (101) and (002). Considering these interactions allowed us to calculate very satisfactorily all the experimental levels, and precise sets of vibrational energies and rotational and coupling constants were obtained for the seven most abundant H₂Te isotopic species, namely H₂¹³⁰Te, H₂¹²⁸Te, H₂¹²⁶Te, H₂¹²⁵Te, H₂¹²⁴Te, H₂¹²³Te, and H₂¹²²Te. For the most abundant species, H₂¹³⁰Te, the band centers in cm^-1are &ngr;₀(&ngr;₂) = 860.6563, &ngr;₀(2&ngr;₁) = 4062.8842, &ngr;₀(&ngr;₁+ &ngr;₃) =4063.3697, and &ngr;₀(2&ngr;₃) = 4137.0454. These results, combined with those obtained for other vibrational states, have been used to derive the equilibrium rotational constants and their corrections. Finally, by neglecting the electronic corrections, the equilibrium structure of H₂¹³⁰Te was obtained as follows:r_e(Te–H) = 1.65145(10) Å, _e(HTeH) = 90.2635(90)°.