Multiple solutions of inverse vibrational problems from the parametric approach to two-dimensional species

The non-iterative parametric approach to solving two-dimensional inverse vibrational problems is discussed with respect to the search for all multiple solutions. Symmetry force constants for acetylene, ethylene, methane, silane, germane, stannane and their deuterium isotopes, for carbon-12 and carbon-13 isotopes of tetrafluoromethane, as well as for ammonia, phosphine, arsine, stibine and their deuterium isotopes, are determined with high accuracy. Good agreement with force fields cited from other authors is observed. The results for the two-dimensional symmetry species of acetylene and ethylene are compared with results of the iterative method of isotopic molecular force constant invariance (B. Nikolova, Commun. Dep. Chem., Bulg. Acad. Sci., 21/2 (1988) 158).