Geometries and energy separations of electronic states of Pd5

Geometries and energy separations of low-lying electronic states of Pd, with different structures (tetragonal pyramid, C-4v;,,; edge-capped tetrahedron, C-2v,,; trigonal bipyramid, D-3h,,; square planar, D-4h,,; planar pentagon, D-5h,; and tetrahedron, T-d,) are investigated using complete active space multiconfiguration self-consistent-field method (CASSCF) followed by large-scale multi-reference singles + doubles configuration interaction (MRSDCI) computations that included 3.3 million configurations. The (1)A(1), electronic state with tetragonal pyramidal (C-4V,,), the B-3(2), electronic state with edge-capped tetrahedral (C-2V,,) and the E-3' electronic state with trigonal bipyramidal(D-3h,,) geometries are candidates for the ground state of Pd,. Atomization and dissociation energies of Pd, are computed. (C) 1999 Elsevier Science B.V. All rights reserved.