【作者】 汤丽娟；

【导师】 蒋刚；

【作者基本信息】 四川大学 ， 原子与分子物理， 2007， 硕士

【摘要】 锆是反应堆的主要金属，因此锆和锆的氢化物及其同位素有着重要的理论研究价值和应用前景。本文第一部分采用量子力学中密度泛函（DFT）B3P86方法，应用Gaussian03W程序，对Zr原子利用外输基函数，对氢及其同位素分子采用6-311G^*全电子基函数，计算了无外电场和有外电场作用下ZrH₂、ZrD₂和ZrT₂的微观结构以及不同温度下的热力学函数。进一步研究了不同外电场对金属锆吸附氢及其同位素分子的能力的影响。无外电场作用下，采用气固反应生成热力学函数近似方法，计算了不同温度下金属Zr与氢同位素反应的△H^Θ、△S^Θ、△G^Θ及反应平衡压力，导出了反应平衡压力与温度的关系。有外电场作用下，对于极性气体分子的热力学函数没有影响，但对于非极性分子ZrH₂、ZrD₂和ZrT₂，分子的微观结构和热力学函数都发生改变。从而导致不同外电场作用下金属Zr与氢同位素反应的△H^Θ、△S^Θ、△G^Θ及反应平衡压力也随温度发生了变化，导出了反应平衡压力与外电场和温度的关系。比较了无外电场作用和有外电场作用各反应不同温度下的平衡压力，得到外电场和温度对氢同位素在金属Zr表面吸附能力的强弱有明显的影响。在同一温度，外电场从-0.004a.u.～0.004a.u.的变化过程中，氢平衡压力相差六个数量级。由此可以考虑利用外电场和温度同时来改变金属锆吸附氢及其同位素的能力，降低了反应堆中氢的平衡压力，从而ZrH₂能更好的作为原子反应堆的中子慢化剂材料。钛靶是中子发生器的关键技术，钛的氢化物是钛靶的主要成分，对其激发态的研究有重要的意义。本文第二部分利用对称匹配耦合簇相互作用（SAC／SAC—CI）方法，对TiH₂采用了考虑相对论有效原子实势的LANL2DZ基组，研究了TiH₂的基态，单重、三重激发态的微观结构、激发能、振子强度等。为进一步研究多原子分子激发态提供了理论基础。更多还原

【Abstract】 Zirconium is the major metal of nuclear reaction. Zirconium and Zirconiumhydrides and isotopes have important theoretical study value and technologicalapplication. In the first part of the paper, using Density functional theory （DFT）Becke 3P86 method with Gaussian03W program, 8s7p3d external basis set is used bygen command for Zr. 6-311G^* with full-electron basis set is used for hydrogenisotopes. Microcosmic structure of ZrH₂、ZrD₂ and ZrT₂ and thermodynamicfunctions have been calculated in different temperature without external electric fieldand with external electric field. Finally, the relations of the temperatures, externalelectric field and hydrogen isotopes equilibrium pressure can be obtained.In different temperature,△H^Θ、△S^Θ、△G^Θof the reaction of Zirconium andhydrogen isotopes and equilibrium pressure of hydrogen isotopes are calculated,which educe the relations of equilibrium pressure and temperatures. In externalelectric field, the values of thermodynamic functions of polarity molecules have noany changes, but for non-polarity molecules ZrH₂, ZrD₂ and ZrT₂, microcosmicstructure and the values of thermodynamic functions have changes. Then△H^Θ、△S^Θ、△G^Θof the reaction of Zirconium and hydrogen isotopes and equilibrium pressure ofhydrogen isotopes are calculated. The relations of equilibrium pressure andtemperatures are educed, equilibrium pressure is compared in different temperatureand external electric field. It is obtained that the external electric field andtemperature have important effect in adsorption aspect of hydrogen isotopes.At thesame temperature, equilibrium pressure of hydrogen is reduced 10^-6 from F=-0.004a.u.to 0.004a.u. Therefore, it is considered that the external electric field and temperature are used to change the ability of adsorption of hydrogen isotopes, which is provedthat the Zirconium hydride is the better neutron moderator.14Mev neutron generator of the D-T fusion reaction is regarded as an importantneutron source. T-Ti target is the key technologies of the neutron generator. It hasimportant meaning to study the excited state. In the second part of the paper, using thesymmetry-adapted cluster-configuration interaction （SAC/SAC-CI）, the ground,excited states of TiH₂ molecule are calculated by LANL2DZ basis set, which isconsidered the relativistic effective core potential. Microcosmic structure of ground,excited states are optimized. Excitation energy and oscillation strength are calculated.It offered the theory base for polyatomic molecules.更多还原