CASSCF calculations of the multipole moments and dipole polarisability functions of the X 2Σ+ and A 2Π states of CO+

The potential energy curves, dipole, quadrupole and octopole moments and dipole polarisabilities have been calculated at CASSCF level using a [8s6p3d] basis for the ground X 2Σ+ state of CO+ as a function of internuclear distance. In addition the potential energy curves, as well as the dipole, quadrupole and octopole moments have been calculated for the excited A 2Π state. Results are compared with experimental values of the quadrupole moment and polarisability of the X 2Σ+ state determined from recent multiphoton studies of CO nf-Rydberg series.