SPECTROSCOPIC PROPERTIES AND POTENTIAL-ENERGY CURVES OF SOME LOW-LYING ELECTRONIC STATES OF ALO, ALO- AN AB-INITIO CASSCF STUDY(, LAO, AND LAO+ )

Results of CASSCF state-averaged calculations on the lowest electronic states of LaO and LaO+ are reported in this work. For comparison, som e low-lying electronic states of AlO and AlO+ are also reported. The g round state of LaO was found to be the X(2) Sigma(+) (R(e) = 1.987 Ang strom, omega(e) = 794 cm(-1)) with a low-lying A(2) Delta excited stat e. Five more excited states below 26000 cm(-1) were found. The first i onization potential (IP) is found at 5.16 eV, resulting in an X(1) Sig ma(+) ground state for the LaO+ diatom, in opposition to AlO+ for whic h and X(3) Pi ground state has been found. Analysis of the wave functi ons, dipole moments, and Mulliken populations reveal that the bonding is quite ionic in both systems. (C) 1994 John Wiley & Sons, Inc.