Geometries and energy separations of electronic states of Pd5

Geometries and energy separations of low-lying electronic states of Pd5 with different structures (tetragonal pyramid, C4v; edge-capped tetrahedron, C2v; trigonal bipyramid, D3h; square planar, D4h; planar pentagon, D5h; and tetrahedron, Td) 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 1A1 electronic state with tetragonal pyramidal (C4v), the 3B2 electronic state with edge-capped tetrahedral (C2v) and the 3E′ electronic state with trigonal bipyramidal (D3h) geometries are candidates for the ground state of Pd5. Atomization and dissociation energies of Pd5 are computed.