自辐射场下UO_2分子光谱研究

Spectrum of UO_2 under inner radiation fields

铀原子和氧原子分别使用相对论有效原子实势（Relativistic Effective Core Potential）和6-311＋G （d）基组,采用优选的密度泛函 B3P86方法,研究了铀本身产生自辐射场（-0.005～0.005 a.u.）作用下UO2基态分子的能隙Eg和谐振频率ν.结果表明：能隙Eg=2.0028 eV、1.9974 eV,接近实验值2.1 eV, UO2在自辐射场中具有半导体性质；反对称伸缩振动频率ν3（σg ）、弯曲振动频率ν2（πu ）和对称伸缩振动频率ν1（σg）与实验值776.1 cm-1、225.2 cm-1、765.4 cm-1基本吻合.

A density functional method DFT/B3P86 with relativistic effective core potential basis for U and 6-311＋G（d）basis for O has been used to study the energy gap and harmonic frequency of UO2 ground state molecule under different inner radiation fields ranging from -0.005 to 0.005 a.u..The re-sults show that UO2 has the semiconductor nature in the radiation field,the experimental value of energy gap is 2.1 eV,the calculated value of this article is Eg=2.0028 eV and 1.9974 eV,which have certain reference value;The antisymmetry expansion vibrational frequencyν3 （σg）is close to experimental value 776.1 cm-1 in the electric field,the bending vibrations frequencyν2 （πu）and the symmetrical expansion vibrational frequencyν1 （σg）are all close experimental value 225.2 cm-1 and 765.4 cm-1 .