MOLECULAR-STRUCTURE AND VIBRATIONAL POTENTIAL FUNCTION OF HGI2-ELECTRON DIFFRACTION STUDY

For the first time in electron diffraction structure analysis of polyatomic molecules the direct parameterization of an intensity function on force constants and equilibrium interatomic distances is applied. Following this procedure, all harmonic valence force constants of the HgI2 molecule and the equilibrium interatomic distance HgI in the harmonic approximation have been determined by gas-phase electron diffraction assuming the equilibrium geometry to be linear. On the basis of vibrational frequencies calculated from the force constants thus obtained, a critical analysis of available spectroscopic data is given. By combined use of electron diffraction and most reliable spectroscopic data treated as independent observables the best values for harmonic valence force constants are obtained. The anharmonicity in the bending vibrational potential is also examined. It is shown that, to a good approximation, the bending vibration may be regarded as being harmonic at least for small vibrational quantum number values. © 1979.