Molecular rotational Zeeman effect in HOF, a comparison with H2O, F2O, and other fluorine containing molecules; and dipole moments of HOF and DOF

Abstract

The linear and quadratic rotational Zeeman effect in HOF has been observed with a high magnetic field. The magnetic susceptibility anisotropies are 2χaa −χbb −χcc = (−19.6±0.6) × 10−6 erg/G2·mole and 2χbb −χaa −χcc = 12.8±1.2 (the a axis is nearly along the OF bond and the c axis is perpendicular to the molecular plane); the molecular g values are gaa = 0.642±0.001, gbb = −0.119±0.001, and gcc = −0.061±0.001 and the molecular quadrupole moments are Qaa = (0.2±0.4)×10−26 esu · cm2, Qbb = 1.9±0.8, and Qcc = −2.1±1.1. These results are compared with H2O and F2O. The effect of in-plane fluorine substitution on the out-of-plane minus the average in-plane magnetic susceptibility anisotropy, Δχ, is discussed for a number of molecules and additive values are obtained for each successive fluorine substitution for planar molecules. These contributions to Δχ are first fluorine = +4.5±1.2, second F = +2.5±1.1, and third F = +0.6±0.8. These trends are explained in terms of changes in hybridization of the atom to which the fluorine is bonded. These values are used with results on mono- and difluorobenzene to estimate Δχ for benzene and trifluorobenzene. The electric dipole moments were obtained by the Stark effect and are HOF: μa = |0.37|±0.10 and μb = |2.20|±0.10. The total electric dipole moment of HOF is μ = |2.23|±0.10 D. The electronic structure of HOF is discussed in light of these results.