Bending Of Adsorbed FCN And FNC Molecules Induced By The Renner-Teller Effect

It is shown that the bending of FCN and FNC molecules adsorbed on Si (100) - (2 × 1) surface, is due to the Renner-Teller effect induced by the orbital charge transfers by adsorption. From ab initio calculations of free FCN and FNC and the molecules adsorbed on the model Si₉H₁₂ cluster, the orbital charge transfers to and from the molecules were calculated, the vibronic coupling constants were estimated, and the curvature K of the adiabatic potentials for the bending coordinate of adsorbed molecules was evaluated. Calculations show that for both side-on adsorbed species, as well as for end-on adsorbed FNC molecule K<0 that leads to their bending. For the end-on adsorbed FCN K>0, and this molecule remains linear