Molecular Zeeman spectra of 6,7Li 79,81Br

Abstract

The molecular Zeeman spectra of the four isotopes of lithium bromide have been investigated using a molecular beam electric resonance apparatus augmented with a magnet in the resonance region. Values for the rotational magnetic moment, nuclear shielding anisotropies, diamagnetic susceptibilities, bromine nuclear magnetic moment, and quadrupole moment of the electron distribution for each isotope in the ν = 0 vibrational level and J = 1 rotation level were obtained from these data. For 7Li79Br, gJ = 0.112056(64), σBrT = − 0.000321(82), σLiT = − 0.0000480(42), ξT = 2.35(50) × 10−30 erg G−2 · molecule−1, μBr = 2.1049(8) nuclear magnetons, and 0<Qe>1 = 1.00(10) × 1015 cm2. Values of these parameters for 6Li79Br, 6Li81Br, and 7Li81Br are also reported. Unlike most previous experiments of this type, no static electric field is applied to the resonance region. The motional electric field which the molecules see as they travel through the magnetic field serves as the parity mixing electric field which is necessary for the transition process. The linear velocity dependence of this field tends to cancel the inverse velocity dependence in the interaction time. The theoretical line shape has been investigated by computer.