Molecular g Values, Magnetic Susceptibility Anisotropies, and Molecular Quadrupole Moments in Ethylene Oxide

Abstract

The first‐ and second‐order molecular Zeeman effect has been recorded in ethylene oxide to yield the molecular g values and magnetic susceptibilityanisotropies in the molecule. The magnetic susceptibilityanisotropies are 2χ aa − χ bb − χ cc = + (18.06 ± 0.58) × 10 −6 and 2χ bb − χ aa − χ cc = + (0.78 ± 0.97) × 10 −6 erg / G 2 · mole . The b axis bisects the COC angle and the a axis is also in the COC plane. Only the relative signs of the g values are experimentally determined. Arguments are presented which favor one of the two sets of signs giving g aa = − (0.0946 ± 0.0003) , g bb = + (0.0189 ± 0.0004) , and g cc = +(0.0318 ± 0.0006 . The molecular quadrupole moments, with this choice of signs, are Q aa = + (2.5 ± 0.4) × 10 −26 , Q bb = − (4.3 ± 0.5) × 10 −26 , and Q cc = + (1.8 ± 0.8) × 10 −26 esu · cm 2 . The diagonal elements in the paramagneticsusceptibilitytensor are χ aa p = (60.6 ± 0.3) × 10 −6 , χ bb p = (67.3 ± 0.5) × 10 −6 , and χ cc p = (88.3 ± 0.5) × 10 −6 erg / G 2 · mole . The known value of the average magnetic susceptibility is combined with our values for the paramagneticsusceptibilities and anisotropies of the total susceptibility to yield the diagonal elements in the total and diamagneticsusceptibilitytensors. The total susceptibilities are χ aa = − (24.7 ± 0.7) × 10 −6 , χ bb = − (30.4 ± 0.7) × 10 −6 , and χ cc = − (37.0 ± 0.8) × 10 −6 erg / G 2 · mole and the diamagneticsusceptibilities are χ aa d = − (85.4 ± 0.9) × 10 −6 , χ bb d = − (97.7 ± 1.1) × 10 −6 , and χ cc d = − (125.4 ± 2.0) × 10 −6 erg / G 2 · mole . The second moment of the ground‐state electronic charge distribution is 〈a 2 〉 = (16.3 ± 0.4) × 10 −16 , 〈b 2 〉 = (13.3 ± 0.4) × 10 −16 , and 〈c 2 〉 = (6.8 ± 0.4) × 10 −16 cm 2 .