Electronic structure and chemical bonding in the ground and low-lying electronic states of Ta2

Authors

  • Antonio Carlos Borin,

    Corresponding author
    1. Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748. 05508–900 São Paulo, SP, Brazil
    • Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748. 05508–900 São Paulo, SP, Brazil
    Search for more papers by this author
  • João Paulo Gobbo

    1. Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes, 748. 05508–900 São Paulo, SP, Brazil
    Search for more papers by this author

Abstract

The electronic structure and chemical bonding of the ground and low-lying Λ − S and Ω states of Ta2 were investigated at the multiconfiguration second-order perturbation theory (CASSCF//CASPT2) level. The ground state of Ta2 is computed to be a X3Σmath image state (Re = 2.120 Å, ωe = 323 cm−1, and De = 4.65 eV), with two low-lying singlet states close to it (a1Σmath image: Te = 409 cm−1, Re = 2.131 Å, and ωe = 313 cm−1; b1Γg: Te = 1,038 cm−1, Re = 2.127 Å, and ωe = 316 cm−1). These electronic states are derived from the same electronic configuration: |13σmath image14σmath imagemath image13πmath image〉. The effective bond order of the X3Σmath image state is 4.52, which indicates that the Ta atoms are bound by a quintuple chemical bond. The a1Σmath image state interacts strongly with the X3Σmath image ground state by a second-order spin-orbit interaction, giving rise to the (1)0math image (ground state) (dominated by the X3Σmath image Λ − S ground state) and (9)0math image (dominated by the a1Σmath image Λ − S state) Ω states. These results are in line with those reported for the group 5B homonuclear transition metal diatomics. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

Ancillary