Microwave spectrum and selenol internal rotation of 2-propaneselenol

Abstract

Microwave spectra of 2-propaneselenol and its deuterated species were measured and assigned for the gauche and trans isomers. The double minimum splittings of the gauche isomers were directly observed from b-type transitions, which were assigned with the aid of a double resonance technique. Rotational constants and torsional splitting of the gauche isomer of the parent species were determined to be A = 7802.50 ± 0.75, B = 2847.68 ± 0.04, C = 2242.03 ± 0.03, Δ A = −2.52 ± 0.74, Δ B = 0.02 ± 0.05, Δ C = −0.34 ± 0.03, and Δ ν = 368.91 ± 0.94 MHz, where Δ A, and Δ B, and Δ C are the differences of the rotational constants between the (+) and (−) states. From the torsional splittings and the energy differences of the two isomers of the parent and SeD species, Fourier coefficients of the selenol internal rotation potential function were determined to be V 2 = −88 ± 15, V 3 = 1543 ± 29 cal/mole on the assumption of V 1 = 0. Dipole moments and their components were also obtained for the two isomers.