VIBRATIONAL CHARACTERISTIC FEATURES AND BAND INTENSITIES IN SOLVING 2-DIMENSIONAL INVERSE VIBRATIONAL PROBLEMS

An iterative approach to solving the inverse vibrational problem is used for two-dimensional molecular force field species and all their multiple solutions are obtained. Two methods, one of isotopic molecular force constant invariance and another of differential increments of the force constants, are applied to methane, silane, germane, stannane, ammonia, phosphine, arsine, stibine and their deuterium isotopes, as well as to tetrafluoromethane and its carbon-13 isotope. Criteria for physical significance of each solution based on the characteristic features of the normal vibrations are utilized in discriminating between the multiple solutions. The vibrational intensities are used in an attempt to determine the sip combination for the dipole moment derivatives with respect to the normal coordinates. The force constant results agree very well with those obtained by the parametric approach to the two-dimensional inverse vibrational problem solved for the same molecules [B.M. Nikolova, J. Mol. Struct., 291 (1993) 123].