Molecular structures of acetylene derivatives of tin 6. Molecular structure of bis(trimethylstannyl) acetylene and analysis of vibrational spectra ofits isotopomers by scaling of quantum-chemical force field

The geometry and force fields of the bis(trimethylstannyl)acetylene molecul e (a conformer with D-3d symmetry corresponding to a minimum of the total e nergy of the molecule) were calculated by the RHF and MP2(fc) methods. The effective core potential in SBK form with the optimized 31G* valence basis set was employed in the case of Sn atoms. The 6-31G** and 6-311** basis set s were used for carbon and hydrogen atoms. Vibrational spectra of the light and perdeuterated isotopomers of bis(trimethylstannyl)acetylene were inter preted using the procedure of scaling the quantum-chemical force fields.