自辐射场下UO分子光谱研究

Molecular spectra of UO 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（-0.005-0.005a.u.）作用下UO基态分子的能隙Eg和谐振频率ωe.结果表明：UO分子在自辐射场中谐振频率ωe与实验值819.8cm-1基本吻合.Eg随自辐射场的增大而增大,但增大的趋势减少,占据轨道的电子难以被激发至空轨道而形成激发态,UO分子在自辐射场中更趋于稳定,可以阻止O2、CO2等扩散到表面内层而腐蚀铀表面,有利于了铀在自辐射场中抗腐蚀.

A density functional method DFT/B3P86 with relativistic effective core potential basis for Uand 6-311＋G （d） basis for O is used to study the energy gaps and harmonic frequencies of ground stateUO molecule under different inner radiation fields ranging from -0. 005 to 0. 005 a. u.. The resultsshow that the harmonic frequency we is close to experimental value 819.8cm-1 under different inner radi-ation fields. The energy gap is found to increase with the increasing inner radiation field. The electron ofoccupied orbital is difficult to stimulate to empty orbital and to transform into excited station. The UOmolecular is more stable in inner radiation fields, so it can prevent 02, CO2 and so on to proliferate tosuperficial inner layer and then to corrode the uranium surface, which contributes to the uranium corro-sion prevention in inner radiation fields.