【摘要】 用杂化密度泛函(B3LYP)方法,Pu原子采用相对论有效原子实势(RECP),O原子采用全电子6-311g(d)基组优化了PuO,PuO2,Pu2O3的分子结构,得到了相应的平衡几何构型,并计算了红外振动频率(IR)、Raman光谱.结果表明:PuO,PuO2分子基态几何构型和振动频率与实验值相符.对Pu2O3分子可能的构型和多重性进行结构优化,发现Pu2O3分子基态为11B2的C2v构型,给出了Pu2O3分子基态结构的红外和拉曼光谱数据、力常数等系列数据,并对振动频率的峰值进行了指认.通过自然键轨道(NBO)分析,发现由钚到氧的电荷转移.相对于PuO和PuO2分子,在Pu2O3中形成较弱的Pu—O键.分析自旋布居,发现在这些分子中,自旋磁动量大都由Pu原子的5f电子贡献,而氧原子的2p轨道往往贡献反平行的自旋.更多还原

【Abstract】 Employing hybrid HF/DFT functional in conjunction with the relativistic effective core potential for Puatoms and all-electron basis set 6-311g（d） for Oatoms, the equilibrium geometrical structures of PuO, PuO₂ and Pu₂O₃ molecules are obtained in the geometry optimization. The infrared and Raman spectra are also calculated. The bond lengths and harmonic vibration frequencies of ground states of PuO and PuO₂ molecules are all in agreement with available experimental data. In geometry optimization of Pu ₂O₃ molecule, we have tested more than twenty initial structures with different spin multiplicities （1, 3, 5, 7, 9, 11 and 13）. A C₂v geometry corresponding to electronic state of ¹1B₂ is considered as the ground state of Pu₂O₃ molecule. The harmonic frequency, IR intensity, Raman scatting activity and depolarization ratio of Pu₂O₃ molecule are obtained for the first time in theory. The vibrational modes corresponding to the maximum peaks are assigned for PuO₂ and Pu₂O₃ molecules. In all studied molecules, the charge transfers from Pu to Oatoms are found from natural bonding orbital analysis （ NBO）. Relative to PuO and PuO₂ molecules corresponding to Pu-O single-bond, the interactions between Pu and O in Pu₂O₃ are much weaker. The spin magnetic moments of studied molecules stem mainly from the 5 fatomic orbitals of Pu atoms, but for Oatoms the antiparallel spins from 2 patomic orbital are exhibited.更多还原