title: A new set of bending Td symmetry coordinates for MX4 molecules.
abstract: The conventional set of Td symmetry coordinates for the bending modes of MX4 molecules can lead to ambiguous geometries when displacements from equilibrium are large. It is proposed here to use internal coordinates that are haversines of the bending angles divided by their sum. The A1 representation becomes a constant, enabling recovery of the bending angles unambiguously, analytically, and without approximation.
authors.affiliation: Department of Physics and Technology, Bronx Community College of The City University of New York, University Avenue & West 181st Street, Bronx, New York, 10453.
authors.forename: David
authors.initials: D
authors.lastname: Schmidling
keywords: MX4; Td; bending coordinates