基于第一性原理的密度泛函理论,在未考虑和考虑自旋-轨道耦合(SOC)的情况下分别优化拓扑绝缘体Bi2Se3、Bi2Te3和Sb2Te3的结构,计算它们的声子谱及热力学性质.基于广义梯度交换相关泛函及SOC效应,计算得到三种物质的声子频率比不考虑SOC时更吻合实验数据.最后计算出三种物质的赫尔姆赫兹自由能F,内能E,等体热容CV和熵S随温度的变化趋势.

Adsorption separation method is one of effective methods to detect radioactive xenon isotopes.In order to select well adsorptive xenon adsorbent,the adsorption properties of Xenon on one of activated carbon and three kinds of carbon molecular sieves was studied by static adsorption and dynamic adsorption.The adsorption properties of Xenon in materials were researched of 273 Kand 298Kby static adsorption,dynamic adsorption have been accomplished and the effect of temperature and gas flow rate on the dynamics adsorption coefficient has also been discussed.The experimental results show that TDX-01 carbon molecular sieve has the most excellent dynamic adsorption property.At a temperature of 20℃,under the condition of200mL/min,the dynamic adsorption coefficient of xenon on TDX-01 reached 2 103.3mL/g,is 3times of activated carbon,and 2times of 601.IR spectrogram and the titration experimental data present that the functional groups have no effect on the Xenon adsorption properties.All experimental result imply that the pore structure characteristic of the TDX-01 carbon molecular sieve are the main reason of xenon excellent adsorption characteristics.

The research is focused on the equilibrium geometry and energy of the ground state V_2molecule based on the density function method BLYP with the basis set DZVP-GGA,the computational PEC is fitted to analytical potential energy functions using the 9-parameter Murrell-Sorbie function,the force constants and spectrum data are obtained according to fitted parameters.On that basis,spin polarization effect of the V_n(n = 2～4) molecules have been studied.Results show that ground electronic states of V_2,V_3 molecules are X~3∑_g~-,X~4A_1 respectively,which exist spin polarization effect,the ground electronic state of V_4molecules is X~1A_g,which don't exist spin polarization effect.

基于电子与核振动近似方法,应用密度泛函B3P86方法和相对论有效核势SDD计算,结合统计热力学方法,研究了100 K～1000 K温度范围内Pd与H2、O2反应的标准生成热力学函数以及反应平衡压力与温度的关系.结果表明:Pd与H2、O2反应是放热反应,Pd原子吸附H2的放热量大于吸附O2的放热量,温度升高不利于吸附反应进行;Pd对O2的自发吸附温度很低,室温下几乎不能进行,而对H2的自发吸附温度可高达500 K以上;在100 K～284.394 K可自发吸附O2和H2的温度范围内,O2的反应平衡压力比H2的平衡压力高出9～18个数量级.因此,O2作为杂质气体对目标反应Pd—H2的影响非常有限.

本文基于DTO(～X1A1)分子的多体展式分析势能函数,用准经典的Monte-Carlo轨迹法研究了D+OT (0,0)体系的分子反应动力学过程.结果表明,在碰撞能低时(＜92.048 kJ mol-1),可以生成长寿命DTO(～X1A1)络合物,并且该络合反应是有阈能反应,这一结论与用多体项展式理论计算的DTO分子势能曲线结果一致.随碰撞能增加,逐渐出现置换产物DT和OD,最终分子被完全碰散成D,T和O原子,而且反应D+OT(0,0)→OD+T,D+OT(0,0)→DT+O和D+OT(0,0)→D+T+O也是有阈能反应.

根据同位素效应,导出OT分子第一激发态的光谱常数.用密度泛函理论的B3P86方法,对氘、氚、氧原子采用6-311G **全电子基集合,应用Gaussian98程序对DTO分子结构进行几何优化计算,得到了其稳定结构的几何构形、能量和力学性质,根据微观可逆性原理分析了其可能的离解极限,并用多体展式理论方法研究其分析势能函数.结果表明,势能函数等值势能面图能清晰地再现DTO分子的结构特征和离解能;氘原子与oT的反应及氚原子与OD的反应均是有闽能的反应,且二者的反应阈能不等.

The structures of PdCO2,PdCO,and PdH are optimized by the relativistic effective core potential(RECP) and the density functional theory B3P86 method.The results show that the stable geometry of Pd-CO2 molecule is plane structure.The ground state of PdCO2 is(X～1A′) of Cs group.The structure parameters of RPdC,RCO,RC O′ and∠OCO′ are 0.203 0 nm,0.118 3 nm,0.121 0 nm and 154.215°,respectively.For PdCO molecule,the ground state is 1+,and the structure parameters of R(PdC),R(CO),and ∠PdCO are 0.183 4 nm,0.114 0 nm,and 180°,respectively.The ground state of PdH is 2,and the bond length is 0.152 6 nm.Furthermore,the thermodynamic functions of PdCO2,PdCO,and PdH are also calculated according to electronic-vibration approximation.And the relationships of the equilibrium pressures with temperatures are obtained.The results indicate that the poisoning effect of CO2 is due to the adsorption of O and CO which dissociates from CO2 on palladium surface.

根据扩展的全相对论多组态Dirac-Fock理论,采用"多功能相对论原子结构程序GRASP2(General-Purpose Relativistic Atomic Structure Program 2,1992),考虑量子电动力学(QED)效应和Breit修正,结合惯性约束聚变(ICF)实验室等离子体中已经观察到的激光照射Au元素所产生的一些多重电荷态离子的外壳层共振线跃迁光谱,选取重要的电子组态,计算激光金等离子体中类镓Au48+离子的光谱跃迁波长、能级寿命和能级宽度.计算所得波长值与实验值符合较好,能级寿命与能级宽度的大小关系符合海森堡的能量与时间测不准原理.计算结果对金等离子体中的离子平均寿命、电荷态分布和平均电离度的研究具有一定的参考价值.

Density functional(B3P86/8s7p3d) method for Zr and 6-311g** based function for hydrogen isotopes have been used to optimize the structure of ZrH2,and calculate thermodynamic functions ΔH0、ΔS0、ΔG0 in external electric field.Then,the relations among the temperatures,external electric field and equilibrium pressure hydrogen isotopes can be concluded.The equilibrium press and molecular structure are most changeful from negative electric field to positive electric field.At 293.16 K,hydrogen equilibrium pressure is about 106 times between F=0.004 a.u. and-0.004 a.u..It is proved that has an impact on thermodynamic functions for metal hydrides.

The present work theoretically prove that decomposition type Ⅰ is symmetry forbidden and decomposition type Ⅱ is symmetry permissible which is in fairly agreement with the experiments.

The present work evaluates so-called electron-vibration motion approximation theory (EVMAT) and examines its applicability by the calculations of the ground states ()~3A_2 for TiH_2,TiD_2 and TiT_2,that is,the electronic and vibrational energy and entropy of single molecules TiH_2、TiD_2 and TiT_2 are approximately used as the energy and entropy in their solid states.Based on this,the calculated results of hydrogenation(and its isotopes) thermodymical functions of metallic titanium ΔH~0、ΔS~0、ΔG~0 and equilibrium pressure with temperature are in quite agreeable with experimental data,which confirm the EVMAT theory quite reasonable.The calculational method is density functional theory DFT/6-311G~(**).The solubility of isotopic-hydrogen in metallic titanium have also been calculated,which is acceptable.

The present work is devoted to examine the passivation effect of metallic uraniu by supercritical fluid CO2, which is the most significant. The structure and thermodynamic properties of UC, C, UO2 and supercritical fluid CO, have been calculated, based on which following simultaneous reactions have been examined using chemical equilibrium theory. The results indicate that the Delta G degrees for U (alpha) + CO2 (g) = UO2 (s) + C(Graphite) reaction is -149.8 similar to -632.0 kJ, Delta G degrees for 2U (alpha) + CO2 (g) = UO2 (s) + UC (s) reaction is -725.1 similar to -730.2 kJ, and both Delta G < 0 and equilibrium closely approach products. It is also well known that the supercritical fluid is quite active in kinetics, and therefore the product compounds UC, C and UO2 would be quite stable. After the calculated molar tatio of UC, C and UO2, the stoichiometric ratio of elements is UC0.65 +/- 0.01O1.30 +/- 0.01, which would be useful for XPS observation.

通过微波隐身材料结构设计,对不同厚度的双层碳团簇型微波隐身材料在8.2～12.4GHz频率范围内的吸波性能进行了研究.发现对于不同的厚度要求,要使材料具有良好的吸波性能,应选用具有不同电导率σ的碳团簇型材料.对于总厚度为4mm的材料,反射峰值-31.0dB,有效带宽为3.74GHz;对于变换层为1mm、吸收层为2mm、总厚度为3mm的材料,最小反射率为-40.0dB,有效带宽3.8GHz;对于变换层和吸收层分别为1mm的材料,最小反射率达-33dB,有效带宽为3.3GHz.同时发现,当变换层和吸收层厚度相等时,材料的排列顺序不同,所得的吸收效果会存在很大差异,即材料的方向性显著,而当两者厚度不等时,材料的吸波性能基本与其排列顺序无关,方向性不显著.

理论研究了碳环对称转子的碳环面积与反磁化率的关系; 讨论了对称转子振动谱带的转子结构, 表明转子能级恰好处于微波范围.同时基于量子力学中二维势阱理论和量子化学的离域效应, 揭示出碳环面积越大, 则系统能量越低, 转动常数B和能级间隔会不断减少, 从而有利于吸收低频微波.量子力学方法B3P86/6-311G计算完全证实了理论分析.根据理论指导, 研究了新型碳团簇材料AⅡ在低频段2.0GHz～5.0GHz范围内的微波透射性能, 讨论了碳化温度、厚度、分子材料Ⅱ对其微波透射性能的影响.