Microwave Spectrum, Quadrupole Coupling Constants, and Heavy-Atom Geometry of 2-Bromopropane

Abstract

The microwave spectra of (CH3)2CH79Br, (CH3)2CH81Br, (CH3)213CH79Br, and 13CH3CH79BrCH3 have been examined, and the coordinates of the Br and C atoms have been obtained by the substitution method. The resulting bond distances and bond angles are as follows: r(CBr) = 1.957 Å, r(CC) = 1.508 Å, ∠CCBr = 110.0°, and ∠CCC = 114.2°. The quadrupole coupling constants of (CH3)2CH79Br have been determined to be χaa = 479.5 Mc/sec, χbb = −264.9 Mc/sec, and χcc = −214.6 Mc/sec. Second-order perturbation corrections were included in the analysis of the hyperfine splittings. The quadrupole coupling constants are consistent with χzz = 529.8 Mc/sec, assuming a cylindrical charge distribution, and with χzz = 514.2 Mc/sec, ηbond = 0.0303, assuming that the z axis and the CBr internuclear line coincide.