Molecular structure and relativistic effective core potential for the ground and lowly excited states of PuN

Three types of Relativistic Effective Core Potentials (RECP) with B3LYP methods have been sued to work out the structures for the ground and lowlying excited states of PuN molecule, whose equilibrium nuclear distances and harmonic frequencies have been obtained. The ab initio energy data of PuN have been least-square-fitted to the Murrell-Sorbie potential energy function, from which the corresponding spectroscopic constants, the second, third and forth force constants have been also derived out. The result indicates that the ground state for PuN is X 6Σ+, the others (4Σ+, 8Σ+, 10Σ+) are lowly excited states, basides, SDDRECP with B3LYP method could give the best result which is in good agreement with the experimental result for the harmonic frequency ωe (for ground state X 6Σ+:ωe=840.77 cm-1, ωeχe=5.73 cm-1, De=5.8806 eV, Re=0.1763 nm, Be=0.4084 cm-1, αe=3.3E-03 cm-1). The charge populations, spin densities and dipole moments of PuN molecule to the different RECP's are also been tabled out. (authors)