Electronic states of Al3As2, Al3As2-, Al3As2+, Al2As3, Al2As3-, and Al2As3+

We have computed the optimized geometries and energy separations for the el ectronic scares of Al3As2, Al2As3, and their positive and negative ions usi ng complete active-space MCSCF (CASSCF) followed by multireference singles + doubles configuration interaction (MRSDCI) calculations which included up to 3.9 million configurations. The (2)A(1)(C-2v) State is the lowest elect ronic state of Al3As2 among seven states with distorted trigonal bipyramid structures. The (2)A(1) State and another distorted B-2(1)(C-2v) state are formed from the undistorted E-2' and E-2 "(D-3h) states, respectively, as a consequence of Jahn-Teller effect. The (2)A(2)"(D-3h) State is found to be the ground state of Al2As3 with an undistorted trigonal bipyramid structur e (D-3h) Four electronic states of Al(3)AS(2)(+) and Al2As3+ were computed and their ground states are undistorted (3)A(2)' and (1)A(1)'(D-3h) states for Al3As2+ and Al2As3+, respectively. The (1)A(1)'(D-3h) State is the grou nd state for both Al3As2- and Al(2)ds(3)(-). The atomization energies, adia batic ionization potentials, and other properties for the electronic states of Al3As2 and Al2As3 and a comparison with the Ga analogues are provided. The Al3As2 cluster is shown to differ from Ga3As2 in some states due to a g reater charge transfer from Al(3s) to As(4p) in Al3As2.