The changing features of the molecular intrinsic characteristic contours of H2 molecule in the ground and first excited states calculated by an ab initio method

Abstract The potential acting on an electron in a molecule (PAEM) is formulated, and then given by the concrete expression via CI wavefunction. The molecular intrinsic characteristic contour (MICC) of a molecule is defined as a surface that consists of all the classical turning points of the electron motion within the molecule. At every one of those points the PAEM is equal to the negative of the molecular first ionization energy. MICCs of H 2 molecule in both its ground state 1 Σ g + and first excited state 3 Σ u + at a series of internuclear distances were calculated by means of the MELD ab initio program with full-CI calculation and a separated program. And then the changing features were sketched for the first time. This may provide a fundamental insight into the spatial evolution of the molecular shape during bond-forming and/or bond-breaking processes.