A wealth of structures for the Ge₂H₂⁺ radical cation: comparison of theory and experiment

Five structures of Ge₂H₂ and Ge₂H₂⁺ are investigated in this study. Optimized geometries at the CCSD(T)/cc-pwCVQZ-PP level of theory were obtained. Focal point analyses were performed on these optimized geometries to determine relative energies using the CCSD(T) method with polarized basis sets up to quintuple-zeta. Energy corrections include full T and pertubative (Q) coupled-cluster effects plus anharmonic corrections to the zero-point vibrational energy. Relative ordering in energy from lowest to highest of the five Ge₂H₂⁺ structures is butterfly, germylidene, monobridged, trans, then linear. In neutral Ge₂H₂, the monobridged structure lies lower in energy than the germylidene structure. Fundamental vibrational frequencies and IR intensities were computed for the minima at the CCSD(T)/cc-pwCVTZ-PP level of theory to compare with experimental research. Partial atomic charges and natural bonding orbital analyses indicated that the positive charge of Ge₂H₂⁺ is contained in the region of the Ge-Ge bond.