DENSITY-FUNCTIONAL COMPUTATIONS OF THE DIPOLE-MOMENT DERIVATIVES FOR HALOGENATED SILANES

Electric dipole moments for the equilibrium molecular structures and t heir derivatives along the symmetry coordinates of vibration were comp uted for SiH2F2, SiD2F2, SiH2Cl2, SiD2Cl2, SiH3F, SiD3F, SiH3Cl, SiD3C l, SiHF3, SiDF3, SiHCl3, SiDCl3, SIFCl3, SiF3Cl, SiF4 and SiCl4 by mea ns of the deMon density functional program (A. St-Amant and D. R. Sala hub, Chem. Phys. Lett., 169 (1990) 387). Satisfactory agreement was fo und between the experimental and computed dipole moments for the equil ibrium molecular structures. Perfect agreement was found between the r otational corrections to the dipole moment derivatives calculated by d eMon and those obtained independently from the orthogonality relations hips between the symmetry coordinates and the rotational coordinates. Derivatives of the dipole moments were transformed into the representa tion of the normal coordinates of vibration and the results were compa red with the experimental data which are available on the infrared int ensities of fundamental bands.