用Pu的三种不同相对论有效原子实势(RECP)和密度泛函(B3LYP)方法对PuN基态和低激发态(4Σ+、6Σ+、8Σ+、10Σ+)的分子结构进行了计算,得到了相应的平衡几何构型和谐振频率.采用最小二乘法拟合得到了PuN分子的Murell-sorbie势能函数,在此基础上推导出完整的力常数和光谱数据,并与实验值作对比.结果表明:PuN的基态为X6Σ+,其余为低激发态;在三种RECP中,对于ωe的计算,60个中心电子的SDDRECP/B3LYP给出的结果与实验值符合得比较好(如X6Σ+:ωe=840.77 cm-1,ωeχe=5.73·"cm-1,De=5.880 6 eV,Re=0.176 3 nm,Be=0.408 4 cm-1,αe=3.3E-03 cm-1).计算还给出了相应的电荷布居、自旋密度、电偶极矩和能量特征等系列分子的性质.

Three types of Relativistic Effective Core Potentials (RECP) with B3LYP methods have been used to work out the structures for the ground and lowlying excitated 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 indicate that the ground state for PuN is X()~6Σ~+,the others (()~4Σ~+、()~8Σ~+、()~(10)Σ~+) are lowlying excitated states, besides, SDDRECP with B3LYP method could give the best result which is in good agreement with the experiment result for the harmonic frequency ω_e(for ground state X()~6Σ~+:ω_e=840.77 cm~(-1), ω_eχ_e=5.73?cm~(-1), D_e=5.880?6?eV,R_e=0.176?3?nm,B_e=0.408?4?cm~(-1),α__e=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.