High resolution infrared spectra of (SbHD2)-Sb-121 and (SbHD2)-Sb-123 have been studied in the region of nu(1), the Sb-H stretching fundamental, from 1780 to 1990 cm(-1). The 2 nu(1) stretching overtone band of (SbHD2)-Sb-123, located in the 3640-3790 cm(-1) range, has also been investigated. The SbHD2 molecule is an asymmetric rotor of C-s symmetry with the asymmetry parameter kappa = 0.61. The nu(1) band is of hybrid type, formed by strong C-type and weak B-type transitions, and almost unperturbed. For (SbHD2)-Sb-123, 2092 transitions have been assigned: 70% of these belong to the C component, the other 30% are of B-type. The assigned transitions have been fitted using a Watson type S-reduced Hamiltonian in the lilt representation, with a standard deviation of the fit sigma = 0.45 x 10(-3) cm(-1). In order to determine the ground state parameters all possible ground state combination differences (GSCD) have been generated from the v, transitions. In total, 3942 GSCD up to J '' = 27, K ''(a) = 25, and K ''(c) = 20 have been fitted with sigma = 0.52 x 10(-3) cm(-1). Only C-type transitions have been observed in the weak 2 nu(1) overtone band. The 556 assigned transitions have been fitted with sigma = 2.6 x 10(-3) cm(-1) using the same Hamiltonian as for nu(1). In the nu(1) band of (SbHD2)-Sb-121 771 C-type transitions have been assigned, and the nu(1) = 1 spectroscopic constants obtained from a fit with sigma = 0.70 x 10(-3) cm(-1). Using 618 GSCD the ground state spectroscopic constants of (SbHD2)-Sb-121 have been derived with a = 1.0 x 10(-3) cm(-1). The molecular parameters for the ground and the nu(1) = 1 states of the two isotopologues agree well. The quartic theoretical ab initio force field of SbH3 has been used to predict all relevant spectroscopic parameters for (SbHD2)-Sb-123, (SbHD2)-Sb-121, (SbHD2)-Sb-123, and (SbH2D)-Sb-121. Relations between the harmonic frequencies and between the anharmonicity constants obtained in the expanded local mode theory, for the XH3 -> XH2D/XHD2 isotopic substitution, have been compared with those obtained in the present study. (C) 2010 Elsevier Inc. All rights reserved.
E. Canè, L. Fusina, R. Tarroni, M. Litz, H. Buerger (2011). High resolution infrared study of SbHD2: The ground state and the Sb-H stretching bands nu1 and 2nu1. JOURNAL OF MOLECULAR SPECTROSCOPY, 265, 1-9 [10.1016/j.jms.2010.10.008].
High resolution infrared study of SbHD2: The ground state and the Sb-H stretching bands nu1 and 2nu1
CANE', ELISABETTA;FUSINA, LUCIANO;TARRONI, RICCARDO;
2011
Abstract
High resolution infrared spectra of (SbHD2)-Sb-121 and (SbHD2)-Sb-123 have been studied in the region of nu(1), the Sb-H stretching fundamental, from 1780 to 1990 cm(-1). The 2 nu(1) stretching overtone band of (SbHD2)-Sb-123, located in the 3640-3790 cm(-1) range, has also been investigated. The SbHD2 molecule is an asymmetric rotor of C-s symmetry with the asymmetry parameter kappa = 0.61. The nu(1) band is of hybrid type, formed by strong C-type and weak B-type transitions, and almost unperturbed. For (SbHD2)-Sb-123, 2092 transitions have been assigned: 70% of these belong to the C component, the other 30% are of B-type. The assigned transitions have been fitted using a Watson type S-reduced Hamiltonian in the lilt representation, with a standard deviation of the fit sigma = 0.45 x 10(-3) cm(-1). In order to determine the ground state parameters all possible ground state combination differences (GSCD) have been generated from the v, transitions. In total, 3942 GSCD up to J '' = 27, K ''(a) = 25, and K ''(c) = 20 have been fitted with sigma = 0.52 x 10(-3) cm(-1). Only C-type transitions have been observed in the weak 2 nu(1) overtone band. The 556 assigned transitions have been fitted with sigma = 2.6 x 10(-3) cm(-1) using the same Hamiltonian as for nu(1). In the nu(1) band of (SbHD2)-Sb-121 771 C-type transitions have been assigned, and the nu(1) = 1 spectroscopic constants obtained from a fit with sigma = 0.70 x 10(-3) cm(-1). Using 618 GSCD the ground state spectroscopic constants of (SbHD2)-Sb-121 have been derived with a = 1.0 x 10(-3) cm(-1). The molecular parameters for the ground and the nu(1) = 1 states of the two isotopologues agree well. The quartic theoretical ab initio force field of SbH3 has been used to predict all relevant spectroscopic parameters for (SbHD2)-Sb-123, (SbHD2)-Sb-121, (SbHD2)-Sb-123, and (SbH2D)-Sb-121. Relations between the harmonic frequencies and between the anharmonicity constants obtained in the expanded local mode theory, for the XH3 -> XH2D/XHD2 isotopic substitution, have been compared with those obtained in the present study. (C) 2010 Elsevier Inc. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
