Electronic Structures of the CH Radical

The electronic states and the molecular constants of the ground and lower excited states of the CH radical are calculated by the Heitler-London method and the LCAO-SCF method. In the former, s2p2, sp3, and p4 configurations of the carbon atom are taken into account for the wave function, and in the latter LCAO-SCF MOs are calculated for the ground and lower excited states. The interactions between all electrons are considered, but the orthogonal relationship between the 1s orbitals of carbon and hydrogen is assumed. As much as possible, the energy integrals were computed from SCF AOs. The results are in general agreement with the observations and Mulliken's prediction. It is concluded that without configuration interaction no satisfactory LCAO-SCF calculation can be made to determine the ground state of the radical as well as of the electronic levels of the carbon atom.