Excited-state potential energy surfaces of silaethylene: a MRCI investigation

Abstract

Extended MR-CISD calculations have been performed for vertical electronic excitations and for excited-state energy surfaces of silaethylene. Stationary points and conical intersections have been determined using recently developed analytic MR-CI gradients and non-adiabatic coupling terms. The calculations show that in vertical excitations the ππ* (V) state is the lowest excited singlet state. The torsion around the CSi bond is the dominant stabilizing factor, as in the case of ethylene. However, in marked contrast to ethylene this torsion leads directly to a conical intersection with the ground state. CH₂ and SiH₂ pyramidalization and hydrogen migration pathways also have been investigated. Both modes are not expected to play a significant role concerning the excited-state lifetime of silaethylene.

Acknowledgments

This work was supported by the Austrian Science Fund within the framework of the Special Research Program F16 and by the Project No. P14442-NO3. The authors also gratefully acknowledge a travel grant by the University of Vienna for one of us (M.P.). The calculations were performed in part on the Schroedinger II Linux cluster of the Vienna University Computer Center.

Notes

Present address: Institute for Physical and Theoretical Chemistry, Comenius University, Mlynska dolina CH1, SK-84215 Bratislava, Slovakia

Additional information

Notes on contributors

H. Lischka *

Present address: Institute for Physical and Theoretical Chemistry, Comenius University, Mlynska dolina CH1, SK-84215 Bratislava, Slovakia