Searches on the potential energy hypersurfaces of GeCH2, GeSiH2, and Ge2H2

Abstract

Optimum geometries are computed at both the SCF level of theory and the level of second-order perturbation theory for several isomers on the potential energy hypersurfaces of GeCH2, GeSiH2, and Ge2H2, including linear structures, methylene-carbenelike structures, dibridged structures, and monobridged structures. In addition, harmonic vibrational frequencies are computed to characterize these structures as local minima or transition states. All computations employ basis sets of triple-zeta quality on valence electrons with d and f polarization functions on the heavy atoms and p functions on hydrogen. This investigation is the first systematic study to include all of these germanium systems and to employ f-type polarization functions in such a study. Previous investigations of ours indicate that large basis sets such as those employed in this study can, in part, compensate for the lack of a more advanced treatment of electron correlation. While a dibridged global minimum is confirmed for both Ge2H2 and GeSiH2 systems, the C2v isomer, methylenegermene, is found to be the most stable structure for GeCH2. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 925–932, 1998