The Rotational Zeeman Effect in Acetone, its g-Tensor, its Magnetic Susceptibility Anisotropics and its Molecular Electric Quadrupole Moment Tensor; A High Resolution Microwave Fourier Transform Study

Acetone is a molecule with an intermediate barrier for methyl- top internal rotation, and only molecules in the A - state of the tunneling motion exhibit a rigid rotor spectrum. For this state we report the results of a rotational Zeeman effect study of acetone in exterior fields up to 20 kGauss (2 Tesla). From an analysis of the observed Zeeman splittings within the asymmetric top approximation the nonzero elements of the g-tensor and the magnetic susceptibility anisotropies were obtained as follows: g = -0.04379 (8), g = - 0.06611 (5), g =-O.O1481 (7), 2ξaa -ξbb - ξcc = - 9.53 (21) 10 erg G mole and 2 ξ - ξ - ξ = 25.57 (18) 10 erg G mole . The nonzero elements of the molecular electric quadrupole moment tensor were derived as Q - 2-77 (13) DÅ, Q = -4.59 (10) DÅ and Q = 1.82 (15) DÅ. Zeeman spectra were also recorded for seveal low-J transitions of molecules in the EE-state of methyl top tunneling (one top tunneling), and so far the same splittings have been found as for the A -species