Deviation of S-O chemical bond of SO2 molecule

The force matrix of the SO2 molecule is calculated without using a priori assumptions on the nature of the force field. The calculations are performed using a comparatively new 3N-matrix method based on the experimental frequencies of characteristic normal vibrations of (SO2)-S-32-O-16, (SO2)-S-32-O-18, and (SO2)-S-34-O-16 molecules. It is shown that the direction of the chemical bond between chemically bound S and O atoms does not coincide with the direction of the straight line that connects the nuclei of these atoms. The angle between these directions (deviation angle) is determined. In the approximation of harmonic vibrations, the deviation angle is Delta = 1.092A degrees. The effect of the anharmonicity of vibrations on the deviation angle is evaluated.