On the Topology of the Electron Density of H3+

Abstract

The topology of the electron density Rho(r) of H3+ is revisited by series of ultra fine tuned geometry optimizations within Hartree-Fock self-consistent virial scaling (SCVS) approach in combination with correlation consistent cc-pVXZ basis sets. The calculations are extended to approach the Hartree-Fock complete basis set (CBS) limit. It is discussed that within such tuned ab initio calculations, the sources of errors that are mapped to the final density matrix in normal calculations, are essentially eliminated. The results of electron density analysis on such error free Rho(r) function via the quantum theory of atoms in molecules (QTAIM) confirm unambiguously the non-nuclear attractor (NNA) as the fundamental topological building block (together with three H atomic basins) to describe the bonding in H3+ ion molecule. The convergence patterns of the values of different density dependent properties toward CBS limit are also explored. It is reported that the cc-pVXZ sets are not only energy consistent but also density consistent. Therefore on the basis of this important density consistency behavior, the CBS limit values of different atomic and bonding indexes are estimated and ultimately the structure and bonding pattern of H3+ are concluded.