Sequential bond energy, binding energy, and structures of \({\mathrm{\bf Be}}^{+}\cdot {\left({\mathrm{\bf H}}_{2}\right)}_{1-3}\) complexes

The binding energy and structures of the Be cations with H₂ molecules are studied theoretically at the MP2/aug-cc-pVTZ method level. The structures of the \({Be}^{+}\cdot {\left({H}_{2}\right)}_{1-3}\) complexes are determined. A tee and a vee-shaped structure are obtained for mono- and di-ligated complexes. Trigonal prism geometry is discovered in the tri-ligated complex. The sequential bond energies of the \({Be}^{+}\cdot {\left({H}_{2}\right)}_{1-3}\) complexes are also examined. The variation in the trend in sequential bond dissociation energies that have been observed may be due to variations in the electrostatic interaction energies, electronic charge transfer, and repulsive forces between the H₂ ligands in these complexes.

Graphical abstract

The figure represents the potential energy surface (PES) of the interaction between the Be⁺ ion and hydrogen molecule, H₂, at different polar angle, θ.. Our results show that the Be⁺,H₂ complex exhibits a T configuration in which the cation is vertically directed a long the mid bond length of H₂ molecule. The PES diagram has a potential well depth at around - 6.0 kcal/mol.