Analysis of the ν3 bands of natural OsO 4 from high-resolution Fourier transform infrared spectroscopy

Abstract

The infrared spectrum of natural OsO 4 has been recorded on a high-resolution (1.2 × 10 −3 cm −1) Fourier Transform spectrometer, in the spectral range 930 to 985 cm −1, which covers mainly the ν 3 fundamental bands. The absolute calibration of wavenumbers is about 0.2 × 10 −3 cm −1 with respect to CO 2. Using the tensor Hamiltonian of J. Moret-Bailly [ Cah. Phys. 15, 237–316 (1961); J. Mol. Spectrosc. 15, 344–354 (1965)], developed up to the fifth order of approximation, the ν 3 bands of the four main isotopic species of m OsO 4 ( m = 192, 190, 189, 188) are analyzed, including transitions with J values up to about 50. For each isotope, 18 molecular constants are derived for the excited ( v 3 = 1) state. The scalar constants of the ground state are also refined, leading to β 0 = B 0 = 0.13490(15) cm −1, γ 0 = − D s0 = −2.79(36) × 10 −8 cm −1, and π 0 = 1.057(95) × 10 −12 cm −1. More than 2180 experimental lines are included in the various numerical fits, and are reproduced with an average standard deviation of 0.56 × 10 −3 cm −1.