Calculated Rydberg States of the PO Molecule

Abstract

The Rydberg States of the PO molecule, converging to the ground state of the PO+ ion, are calculated using the LCAO–MO SCF orbitals of the molecular ion core. An adjustment between the observed and calculated values for the energy of the first Rydberg A2Σ+ state gives a value of about 66 400 cm−1 for the ionization potential of PO. The agreement between the experimental and calculated values is very good for the other observed Rydberg states. In the 5300–3800 Å region, no more than four 2Σ+ Rydberg states are expected, which supports the "deperturbation" procedure carried out by Verma. A comparison is made between the p, d, and ƒ complexes in PO and NO. The B2Σ+ state appears to be a valence state corresponding to the electron excitation from an antibonding (vπ)* orbital to a weakly antibonding (uσ)* orbital.