类锂离子(Z=3～100)磁偶和电偶的跃迁几率和能级间隔的相对论计算

采用全相对论多组态Dirac-Fock方法，分别计算了类锂离子（Z＝3－100)的磁偶跃迁1s^23s^2S1/2→1s^22s^2S1/2和电偶跃迁1s^2p^2P1/2→1s^22s^2S1/2的能级间隔，QED贡献和跃迁几率，比较了两者的参数与核电荷数Z的关系的差异，认为原子序数很大时，磁偶跃迁几率不能忽视。     

镁铝类氢类氦类锂离子双电子复合速率研究

 镁铝类氢类氦类锂离子经中间双激发态进行的双电子复合过程在用双示踪元素谱线强度比研究ICF电子温度中占有很重要的地位。计算了双电子复合经不同Rydberg态跃迁通道的复合速率系数，并给出不同离化度的总的双电子复合速率系数的变化规律，比较了它们在不同电子温度和不同跃迁通道的异同，对研究X射线激光、等离子体温度诊断等诸多应用领域提供了有价值的原子数据。     

Density functional study on structural and electronic properties of bimetallic gold--yttrium clusters: comparison with pure gold and yttrium clusters

Employing first-principles methods, based on the density functional theory, this paper investigates the ground state geometric and electronic properties of pure gold clusters, pure yttrium clusters and gold clusters doped each with one yttrium atom. It is shown that the average bond lengths in the Augold--yttrium bimetallic cluster, density functional theory, HOMO--LUMO gap, equilibrium structureProject supported by the Education Committee of Chongqing (Grant No KJ051105) and the National Natural Science Foundation of China (Grant No 10276028).3640, 3640B, 3120A, 3130J9/1/2007 12:00:00 AMEmploying first-principles methods, based on the density functional theory, this paper investigates the ground state geometric and electronic properties of pure gold clusters, pure yttrium clusters and gold clusters doped each with one yttrium atom. It is shown that the average bond lengths in the Augold--yttrium bimetallic cluster, density functional theory, HOMO--LUMO gap, equilibrium structureProject supported by the Education Committee of Chongqing (Grant No KJ051105) and the National Natural Science Foundation of China (Grant No 10276028).3640, 3640B, 3120A, 3130J9/1/2007 12:00:00 AMEmploying first-principles methods, based on the density functional theory, this paper investigates the ground state geometric and electronic properties of pure gold clusters, pure yttrium clusters and gold clusters doped each with one yttrium atom. It is shown that the average bond lengths in the Au$_{n - 1}$Y($n \le $9) bimetallic clusters are shorter than those in the corresponding pure gold and yttrium clusters. The most stable isomers of the yttrium-doped gold clusters tend to equally delocalize valence s, p and d electrons of the constituent atoms over the entire structure. The Y atom has maximum number of neighbouring Au atom, which tends to be energetically favourable in the lowest-energy equilibrium structures, because the Au--Y bond is stronger than the Au-Au bond. The three-dimensional isomers of Au$_{n - 1}$Y structures are found in an early appearance starting at $n$=5 (Au$_{4}$Y). Calculated vertical ionization potential and electron affinities as a function of the cluster size show odd-even oscillatory behaviour, and resemble pure gold clusters. However, one of the most striking feature of pure yttrium clusters is the absence of odd-even alternation, in agreement with mass spectrometric observations. The HOMO--LUMO gap of Au$_{3}$Y is the biggest in all the doped Au$_{n - 1}$Y($n \le $9) bimetallic clusters.     

Mg-Al-N三元团簇的密度泛函理论研究

运用杂化密度泛函方法B3LYP在6-311+G^*计算水平上研究Mg_xAl_yN(x,y=1-5)团簇的结构.对Mg_xAl_yN团簇最低能量结构的稳定性和电子特性进行研究.结果表明,Mg_xAl_yN(x+y≤4)团簇的构型主要是平面结构.Mg_xAl_yN团簇的最低能量结构主要是由Al_nN或Mg_x-1Al_y+1N的构型演变而来.Mg_xAl_yN团簇离解成原子或者较小团簇是相对稳定的.和相邻团簇相比,MgAl₃N和Mg₃Al₃N拥有较高的稳定性.随着团簇尺寸的增加,Mg_xAl_yN团簇同时表现出共价键,离子键和金属键的特点.另外,随着团簇尺寸的增加,团簇的垂直电离势和电子亲合能呈现小的震荡,但并没发现整体的变化规律.     

类氢离子Mg~(11 ),Al~(12 )光谱参数的理论计算及在温度诊断中的应用

采用“多功能相对论原子结构计算程序”GRASP2 (1 992 ) ,分别计算了类氢离子 Mg11 ,Al12 能级之间电偶跃迁 (E1 )的波长、几率和振子强度 ,其中跃迁波长值与实验值相吻合。充分利用计算结果 ,采用等电子线率法对文献 [4 ]的谱线强度比测温实验进行理论上的探讨 ,即利用原子序数相差不大 (ΔZ=1 ,2 )的两种示踪原子相同离化态的同种跃迁谱线进行电子温度诊断 ,以期望提高测温精度     

(SiO_2)_n~-(n≤7)团簇的密度泛函研究

采用密度泛函理论中的广义梯度近似对(SiO2)n-(n≤7)负离子团簇的几何构型进行了优化,并对能量和频率进行了计算.通过对计算结果的分析发现,与近邻尺寸的团簇比较,(SiO2)4-团簇最低能量结构更加稳定;(SiO2)n-(n≥4)团簇的最低能量结构是以(SiO2)4-为基础结构,具有一定的生长规律.     

Density functional study on the bimetallic Ti_mZr_n(n+m ≤ 5) clusters and their interactions with H_2

Equilibrium geometries, stabilities, and electronic properties of small Ti_mZr_n(n + m ≤ 5) clusters were investigated using the density functional method. The ground states were determined, and it was found that the larger clusters and those consisting of more Zr atoms are more stable. The electronic properties of the clusters were discussed based on HOMO-LUMO gaps, vertical ionization potentials(VIP), and vertical electron affinities(VEA). Furthermore, we studied the interactions between those clusters and molecular hydrogen, and found that in all the cases dissociative chemisorptions occurred. According to the chemisorption energies, the pure Zr clusters are relatively more active towards H_2 when compared with the others except Ti_3Zr, which shows the highest activity. The magnetic moments of Ti_mZr_n and Ti_mZr_nH_2 were also compared, and the results show that the hydrogenated clusters have the same or decreased total magnetic moments with respect to the bare clusters except for Ti_3Zr_2.     

TinMg (n=1—10)掺杂团簇的密度泛函研究

采用密度泛函(DFT)中的B3LYP方法,选择sto-3g基组,优化并得到了Ti_nMg(n=1—10)小团簇的基态平衡结构,计算出了掺杂团簇的基态结构的平均键长、对称性、原子化能、能级分布、能级间隙、束缚能、总能的二阶差分. 结果表明,随着团簇原子数的增加,镁原子更容易趋于团簇表面位置,镁-钛平均键长大于钛-钛平均键长,以对称性结构为最稳定的基态结构,且呈多个五角双锥结构. 其中Ti₅Mg和Ti₈Mg的结构更为稳定. 关键词： 密度泛函 钛-镁团簇 基态结构     

类氦离子V~(21 )精细能级结构及跃迁光谱的相对论计算

采用加轨道极化修正的相对论多组态Dirac Fock方法 ,计算了类氦离子V2 1 的跃迁几率和跃迁波长 ,所得结果与实验值吻合 ,比较了极化对能级、能级间隔和不同类型跃迁的影响 ,并讨论了轨道极化修正函数。