The Molecular Zeeman Effect of Norbornadiene, its g-Values, Magnetizability Anisotropies, and Molecular Electric Quadrupole Moment; A High-Resolution Microwave Fourier-Transform Study Combined with Quantum Chemical Calculations

Abstract

The molecular Zeeman effect is reported for norbornadiene at fields near 18 kG. The experimental results are for the molecular (g-values: gaa = 0.02860(16), gbb = 0.05271(11), gcc = 0.00142(26), for the magnetizability anisotropics: 2ξaa – ξbb – ξcc = –0.41(26) · 10-6 erg G-2 mol-1, 2ξ66 – ξcc – ξaa = +40.72(27)· 10-6 erg G-2 mol-1 and for the molecular electric quadrupole moments: Qaa = -1.78(20) · 10-26 esu cm2, Qbb = 3.73(20)· 10-26 esu cm2, Qcc = -1.94(30) · 10-26 esu cm2, with the c-axis of the molecular inertia tensor aligned to the C2v-axis of the equilibrium configuration. The results of ab-initio calculations, using London type atomic orbitals as basis functions, are reported for the g-tensor, the magnetizability tensor and the molecular electric quadrupole moment tensor and are compared to the experimental findings. The possibilities of strain induced magnetizability exaltations and of systematic differences between gas phase and bulk phase magnetizabilities are discussed. © 1998, Verlag der Zeitschrift für Naturforschung. All rights reserved.