The electron in the excited state need not have the same set of quantum numbers as the electron with which it was paired in the bonding orbital
in the ground state before absorption.
Far from the surface and in the absence of a field, the atomic orbitals of A and B hybridize into molecular orbitals which we take to be a low-lying bonding orbital
and an empty antibonding orbital.
Therefore, the CB (conduction band) and VB (valence band) regions show the bonding orbitals
, the non-bonding orbitals and the anti-bonding orbitals.
Table 1S: BCP properties, Wiberg bond index, and electronic configurations for bonding orbitals
of central bonds.