Some theoretical considerations for magnetic vibrational circular dichroism spectra

Abstract

Expressions are derived for the A terms, B terms, and associated partial anisotropy factors relevant for the magnetic vibrational circular dichroism (MVCD) spectra of molecules with nondegenerated ground states. These expressions are derived subject to the approximations of the harmonic fixed partial charge model and the condition of magnetic coupling among only the ground electronic state vibrational levels. Numerical values for partial anisotropy factors calculated from these expressions, when taken in conjunction with the recent MVCD data of Keiderling, suggest the importance of magnetic coupling of the ground electronic state with higher electronic states in the case of B terms. Symmetry constraints on the nonvanishing of such coupling terms also suggest the possible utility of MVCD data for providing spectroscopic and molecular structural information.