The Shape and the Proton Affinity of GeH₅⁺, and the Theory of Its Existence and Breaking up

Abstract

The molecular geometry of GeH₅⁺ has been determined. It is a loose complex of GeH₃⁺and H₂ fragments. The molecular symmetry is C₅, but is not D_3h, proposed by Hartmann et al. The chemical bond of GeH₅⁺ is analyzed in detail with various kinds of technique and from a number of points of view.
The proton affinity of GeH₄ is 7.12 eV. It has been found that the SCF calculation i s sufficient for the absolute value of the proton affinity, since the corrections cancel out to become negligible.
The reason why it is difficult to detect GeH₅⁺ in the proton transfer reaction of GeH₄ has been discussed. Only 0.31 eV is enough to stabilize GeH₅⁺ in reference to GeH₃⁺+H₂. The large amount of energy gained by protonation is distributed among the molecule during relaxation. When the bond between GeH₃⁺ and H₂ gains surplus energy over its bond energy, the bond easily dissociates into fragments.
These results are obtained by the calculation with ab initio LCAO-MO-SCF method using the basis set of double-zeta quality plus a diffuse GTO in each shell. Furthermore, polarization functions are added; f-type for Ge and p-type for H.