硅中Jahn-Teller畸变的双空位超精细相互作用的理论计算

采用扩展的Koster-Slate模型,分别对硅中双空位的两种重要的Jahn-Teller畸变模,计算了缺陷电荷态V₂⁺,V₂^-中未配对电子的超精细相互作用常数a和b,给出与实验符合得很好的结果.由此还定出与实验相符合的能级和对称态:V₂⁺的未配对电子处于能级约为0.3eV的Ag对称态;而V₂^-的电子处于能级约为0.63eV的Bu态;EG1模可能是V₂⁺和V₂^-的最优选的畸变. 关键词：     

硅中四空位扩展的Koster-Slater模型

本文用扩展的Koster-Slater模型计算了硅中V₄^-未配对电子的对称化波函数,用算得的波函数计算了缺陷电子局域在最近邻每个原子上的η²及其s特征α²,和超精细相互作用常数,确定V₄^-处于深能级为0.78eV的A₁对称态,给出与现有实验值相符合的结果。并指出,V₄^-的单个悬挂键上的η²比其它具有单个悬挂键的缺陷小,是由于V₄^-的势分布向一侧有较大偏重所致。 关键词：     

等离子体氧轰击硅生成缺陷的研究

本文对等离子体氧轰击硅产生的缺陷进行了研究。发现等离子体氧轰击在硅中引入两个缺陷E₁(E_c—0.46eV)及E₂(E_c—0.04eV)。测量了缺陷的光电离截面谱,分析表明,缺陷E₂的电子声子相互作用很强,其Frank-Condon移动达0.76eV,缺陷E₁的电子声子相互作用较小,其Frank-Condon移动为0.04eV。由实验结果得到与缺陷E₁、E₂相耦合的声子模分别为hω_p⁽¹⁾=28meV,hω_p⁽²⁾=20meV。 关键词：     

钙钛矿型晶体A(B1/31B2/32)O3中的有序-无序相变

本文利用原子集团变分方法,讨论了A⁺²(B_1/3⁺²B_2/3⁺⁵)O₃系统中有序-无序相变,指出在此系统中相互作用能参数对形成(B_2/3⁺²B_1/3⁺⁵)_1/2:B_1/2⁺⁵=1:1的混合型有序畴和B_{1/3关键词：}     

单原子Al修饰空位缺陷V2C（MXene）对H2气体表面吸附的第一性原理研究

基于第一性原理计算方法,对含空位缺陷的V₂C(MXene)在不同位点修饰单原子Al的相关性能进行系统研究.研究表明,几何优化后得到含空位缺陷的V₂C稳定结构表面能为-3075.53 J/m²,单原子Al修饰本征V₂C单原子的吸附能为1.5511eV、单原子Al修饰空位缺陷V₂C的吸附能为-2.0763 eV,这表明含空位缺陷的V₂C,由于单原子Al的修饰可以明显改善晶体结构稳定性.进一步从态密度、分波态密度、吸氢能力研究发现,各体系态密度和分波态密度均出现分波越过费米能级的现象,表现出较强的金属性;V₂C吸附H₂气体分子吸附能为-7.5867 eV,而空位缺陷V₂C和单原子Al修饰空位缺陷V₂C两个体系对H₂气体分子的吸附能仅为-0.9851 eV、-2.7130 eV,均未能进一步改善V₂C对H₂气体分...     

电子辐照硅层中缺陷能级的研究

用12MeV电子辐照硅p⁺n结,在硅中除引入氧空位E₁(E_c-0.19eV),双空位E₂(E_c-0.24eV)和E₄(E_c-0.44eV)外,还引入缺陷E₃(E_c-0.37eV)。用DLTS方法和反向恢复时间测量研究了这些能级的退火行为,可以看到,E₃的退火温度最高(≈520℃)。由退火特 关键词：     

Mg原子修饰的封闭型六硼烷B6H62-储氢性质的研究

利用密度泛函理论的方法研究了Mg原子修饰的封闭型六 硼烷B₆H₆^2-吸附氢的性能. Mg可以稳定地结合在B₆H₆^2-上, 它可以吸附六个氢分子. 电荷转移所导致的Mg周围电场的增强和体系更大的偶极矩使 得MgB₆H₆^2-比MgB₆H₆具有更好的储氢性能, 储氢密度达到11.1 wt%, 氢分子的平均结合能在0.23 eV/H₂至0.34 eV/H₂之间. 结果表明可以通过控制金属-有机物体系的电荷态来增强电场, 进而改善其储氢性能. 关键词： 6H₆^2-团簇')" href="#">MgB₆H₆^2-团簇 密度泛函理论(DFT) 储氢性能 电荷态     

相互作用能量参数对A(B1/21B1/22)O3系统有序畴形成的影响

本文利用有序-无序相变理论讨论了A(B_1/2¹B_1/2²)O₃系统中的有序-无序相变,半定量地研究了在A(B_1/2¹B_1/2²)O₃系统中相互作用能参数对形成B¹:B²=1:1有序畴的影响,理论计算结果与实验结果基本一致。 关键词：     

Raman紫外双共振研究C2H2分子的碰撞转动弛豫

本文利用受激Raman抽运,选择性地制备了C₂H₂分子电子基态的红外非激活振动能级的单一转动态(X¹∑_g⁺,v″₂=1,J″=9,11,13),并从紫外激光诱导的A¹Au(v′₃=1)←X¹∑_g⁺(v″₂=1)荧光谱,直接测定上述三个转动态的C< 关键词：     

超冷铯分子0u+(6P3/2)长程态的高灵敏光缔合光谱研究

利用发展的调制俘获损耗荧光光谱技术实验测量了超冷铯分子0_u⁺(6P_3/2)长程态的高灵敏光缔合光谱. 光谱探测范围较国际已有报道扩大了60 cm^-1, 观察到25个长程区域新的振动能级. 通过LeRoy-Bernstein公式对振动束缚能数据进行拟合, 获得了超冷铯分子0_u⁺(6P_3/2)态的长程系数C₃ 为16.103±0.010. 构建了超冷铯分子0_u⁺(6P_3/2)态长程区域的势能曲线.     

无定形靶中离子注入的R,Rp,△Rp的理论计算

本文在Thomas-Fermi势能基础上,导出了全射程R的解析解:R=2/a[E^1/2-A₁(arctg(2E^1/2-f)/△^1/2+arctg f/△^1/2)+B₁ln((E^1/2-f)²)/(E-fE^1/2+d) ·d/f²],其中A₁,B₁,f,d和△均为与离子及靶的质量、原子序数有关的常数。结合导出的η=R/(R_p)(R_p指投影射程)比值的双曲线函数关系 η=F(μ)[A₂(μ)+(B₂(μ))/(ε^1/2+C)],和ω=R_p/△R_p(△R_p指投影射程的标准偏差)比值的线性关系ω=A₃(μ)ε^1/21/2+B₃(μ),可简便而又准确地计算R,△R_p,R_p.这里F(μ),A₂(μ),B₂(μ), B₃(μ)和A₃(μ)为μ的代数函数,μ为离子与靶的质量比,C是经验常数.并对η等关系式的物理意义作了讨论。上述公式的计算结果与Gibbons的数值解结果及有关实验结果作了比较,表明可用于元素半导体如Si、二元化合物如GaAs以及三元化合物如SiO₂等;既对较轻离子适用,也对重离子适用,具有一定的普适范围。     

Franck-Condon factors and absolute transition probabilities for the if (B3Π0+-X1Σ+) transition

Improved spectroscopic constants have been used to calculate Rydberg-Klein-Rees (RKR) potentials and Franck-Condon factors for the IF(B³Π₀₊-X¹Σ⁺) transition. The Franck-Condon factors are generally in good agreement with previously calculated values, but differ by as much as 30% for transitions from higher levels of the B-state. Several experimentally measured relative transition moment functions have been evaluated and the best scaled, so that the total transition probability calculated for each B-state vibrational level, A(v'), matched measured values. The scaled function was then used to calculate individual transition probabilities, A(v',v), for the vibronic transitions.     

Properties of single vacancies and of divacancies in copper

The electrical resistivity change at high temperatures due to vacancies was determined as a function of temperature. From the data E^F_1V=1.00 eV, E^B_2V=0.45 eV and about C^tot_V=4 × 10^-4 at the melting point results.     

Investigation of crystal structure and new ellipsometric properties of hexagonal CdS epilayers

High quality hexagonal CdS epilayer was grown on GaAs (1 1 1) substrates by the hot-wall epitaxy method. The crystal structure of the grown CdS epilayers was confirmed to be the hexagonal structure by X-ray diffraction pattern and scanning electron microscopy image. The optical properties of the hexagonal CdS epilayers were investigated in a wide photon energy range between 2.0 and 8.5 eV using spectroscopic ellipsometry (SE) at room temperature. The data obtained by SE were analyzed to find the critical points of the pseudodielectric function spectra, 〈?(E)〉 = 〈?₁(E)〉 + i〈?₂(E)〉, such as E₀, E_1A, E_1B, E^0′, F₁, and two E₂ structures. In addition, the second derivative spectra, d²?(E)/dE², of the pseudodielectric function of hexagonal CdS epilayers were numerically calculated to determine the critical structures. Four structures, such as E^0′F₁, and two E₂ structures, from 6.0 eV to 8.0 eV were observed, for the first time, at 300 K by ellipsometric measurements for the hexagonal CdS epilayers.     

BeCl分子电子激发态的多参考组态相互作用计算

运用含Davidson修正的多参考组态相互作用方法,在aug-cc-pVTZ基组水平上,对BeCl分子基态和相同多重度的几个低电子激发态进行了势能扫描计算.通过群论原理确定各电子态对称性及离解极限.将其中基态(X²Σ⁺)和第一激发态(A²Π})对应的势能曲线拟合到Murrell-Sorbie解析势能函数形式,得到基态(X²Σ⁺)的离解能及主要光谱常数(括号中为文献[6]提供的实验值)为D_e=3.74eV,R_e=0.18173nm(0.17970),w_e=857.4cm¹(847.2),w_ex_e=5.03cm^-1(5.14),B_e=0.7103cm^-1(0.7285),α_e=0.0059cm^-1(0.0069),第一激发态(A²Π)的D_e=3.02eV,R_e=0.18369nm(0.18211),w_e=832.7cm^-1(822.1),w_ex_e=5.93cm^-1(5.24),B_e=0.6953cm^-1(0.7094),α_e=0.0065cm^-1(0.0068),计算结果与实验值符合得较好.另外,通过Level程序求解双原子径向核运动的Schrödinger方程得到J=0时BeCl分子这两个电子态的全部振动能级.     

Cohesive energy of zincblende (A<Superscript>III</Superscript>B<Superscript>V</Superscript> and A<Superscript>II</Superscript>B<Superscript>VI</Superscript>) structured solids

In this paper we present an expression relating the cohesive energy (E _coh in kcal/mol) of A^IIIB^V and A^IIB^VI semiconductors with the product of ionic charges (Z ₁ Z ₂) and nearest-neighbour distance d (Å). The cohesive energy values of these solids exhibit a linear relationship when plotted on a log-log scale against the nearest-neighbour distance d (Å), but fall on different straight lines according to the ionic charge product of the solids. A good agreement has been found between the experimental and calculated values of the cohesive energy of A^IIIB^V and A^IIB^VI semiconductors.     

Microwave spectrum of Trioxane in four excited degenerate vibrational states,especially in the 2ν20 (E) state and the combination state ν7 (A1) + ν20 (E)

The microwave spectra of the Trioxane molecule in the doubly excited degenerate vibrational state 2ν₂₀(E) and in the combination state ν₇(A₁) + ν₂₀(E) are reported for several J values. Molecular constants of these states have been determined. The excited states ν₂₀(E) = 1 and ν₁₉(E) = 1 previously studied by a perturbation formula have been analyzed by a direct diagonalization method of the energy matrix. Parameters which give the variation of the rotational constant B_V as a function of the quantum number v have been obtained.     

一种测定某些离子导体的导电基本参数的新方法

利用低频交变电场在某些离子导体中能引起偏振态改变的光衍射特性,发展了一种测量这些离子导体的导电基本参数的新方法,并且用它测定了α-LiIO₃单晶的基本离子导电参数,测得其载流子的迁移率激活能E_μ=0.36eV;夫仑克耳缺陷的形成能为E_M=0.59eV;300K时正、负载流子的数密度均为1.6×10¹⁷cm^-3,相对浓度均为1.07×10^-5;当所加电场反平行于晶体的自发极化强 关键词：