DFT-predicted structural,vibrational, and bonding properties of XSiO and X2SiO (X=F,Cl, or Br) molecules

The spectroscopic properties of XSiO (X=F, Cl, or Br) have been predicted using the B3-LYP/6-311+G(2d) level of theory. It has been shown that the halogen atom is Si bonded in a bent structure, with ∠(XSiO) bond angles close to 126°. The binding energy of the halogen with the SiO subunit was calculated to be −80.1, −40.9, and −29.3 kcal/mol for FSiO, ClSiO, and BrSiO, respectively. The harmonic frequencies and isotopic shifts have been calculated. A comparison between XSiO and X₂SiO has also been made. For the X₂SiO (X=F or Cl) compounds, the calculated frequencies are in fair agreement with the available experimental data. Characterization of bonding has been investigated with different approaches (natural bond orbital approach, topological analysis of the charge density, and of the electron localization function ELF). © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 1205–1214, 1998