CONFIGURATION-INTERACTION CALCULATIONS ON THE P-2 MOLECULE .3. SPECTROSCOPIC PROPERTIES OF THE A (1)PI(G) STATE, THE A(1)PI(G)-X(1)SIGMA(+)(G) TRANSITION BANDS AND A COMPARISON WITH THE RESULTS FOR THE X(1)SIGMA(+)(G), A(3)SIGMA(+)(U) AND B(3)PI(2,G) STATES AND RELATED TRANSITION BANDS

Extended basis set, multireference configuration interaction calculations were performed on the A (1) Pi(g) excited state of P-2. Excellent agreement with experiment was obtained for a variety of spectroscopic properties, including R(e), omega(e), omega(e)x(e), B-e, alpha(e), T-e and vibrational transition energies for the A (1) Pi(g) --> X (1) Sigma(g)(+) band system. Several assignments of vibrational transitions based on the theoretically derived Franck-Condon spectrum differ from previous experimental assignments. The theoretical results suggest that these transitions should be attributed to the C (1) Sigma(u)(+) --> X (1) Sigma(g)(+) bands whose emission spectrum lies in the same region as the former band system. Pure rotational excitations within the A (1) Pi(g) state are found to be in good agreement with their 'experimental' counterparts. First order properties, such as the quadrupole moments, have been calculated for the A (1) Pi(g) state and compared to their corresponding values in lower-lying states. A detailed comparison is also made between the present results and earlier spectroscopic properties derived for the X (1) Sigma(g)(+), a (3) Sigma(u)(+) and b (3) Pi(2,g) states and related transition bands.