InAs量子环中类氢杂质能级

在有效质量近似下,利用微扰法研究了InAs量子环内类氢杂质基态及低激发态的能级分布。受限势采用抛物形势,在二维平面极坐标下,用薛定谔方程的精确解析解进行计算。数值计算结果显示,电子能级敏感地依赖于量子环半径,能级存在极小值,这是由于限制势采用抛物势的结果。如果减小环的半径,可以增加能级间距。第一激发态类氢杂质能级的简并没有消除,n≥2时简并的能级发生分裂并且间距随半径的增大而增大。电子能级间距还敏感地依赖于角频率并随角频率的增大而增大。第一激发态的简并没有消除,第二激发态的简并被部分地消除。在计算InAs量子环中类氢杂质的基态和低激发态的能级时,角频率改变的影响也是很深刻的。文章结果对研究量子环的光跃迁及光谱结构有重要指导意义。     

SeF_n(n=0,+1,+2)基态及SeF低激发态的势能函数与微观性质

为了弄清氟与硒相互拮抗作用的动力学特征,了解SeFn(n=0, 1, 2)分子离子基态和激发态势能函数及微观结构、性质的基本信息是必要的.本文采用6-311 G**基组、B3LYP方法对SeFn(n=0, 1, 2)分子离子基态进行了结构优化和频率计算,用TDB3LYP/6-311 G**含时方法对激发态B12Π、B22Π进行了计算,得到SeFn(n=0, 1, 2)分子离子基态和SeF分子激发态B12Π、B22Π的平衡几何结构、电子状态、谐振频率、偶极矩、离解能De等性质,并在计算出来的一系列单点势能基础上,用正规方程组拟合Murrell-Sorbie(M-S)势能函数,得到相应态的解析势能函数,光谱参数Be、αe、ωe、和ωeχe,由此计算对应的光谱参数和力学性质.理论计算值与相关文献值吻合较好,说明用B3LYP(TDB3LYP)/6-311 G**方法计算SeFn(n=0, 1, 2)分子离子基态和激发态微观结构性质是可行的.     

C2分子的分析势能函数与垂直电离势

用ａｂｉｎｉｔｉｏ计算方法和实验光谱数据分别导出Ｃ２分子基态Ｘ１Σ＋ｇ和激发态ｄ３Πｇ的Ｍｕｒｅｌ－Ｓｏｒｂｉｅ函数，同时用ＱＣＩＳＤ／６－３１１Ｇ方法优化出Ｃ－２、Ｃ＋２、Ｃ２＋２分子离子基态的平衡核间距，算出Ｃ２分子的垂直电离势，计算数据与实验光谱数据进行了比较。     

普适性双原子分子解析势能函数的研究

提出了一种构造解析势能函数的新方法,由此得到了一种既适用于中性双原子分子又适用于带电双原子分子离子的解析势能函数。本文用八种基本类型的双原子分子——同核中性基态双原子分子Na₂-X1Σ+_g,同核中性激发态双原子分子C₂-A1Π_u,同核带电基态双原子分子离子He+₂-X2Σ+_u,同核带电激发态双原子分子离子N+₂-B2Σ+_u,异核中性基态双原子分子NaLi-X1Σ+_g,异核中性激发态双原子分子BH-B1Σ+,异核带电基态双原子分子离子(BC)--X3Π,异核带电激发态双原子分子离子(CS)+-A2Π等共21个算例对势能函数进行了验证并与RKR (Rydberg-Klein-Rees)实验数据进行了比较,计算结果与RKR数据符合很好。     

有限深抛物势量子环类氢杂质能级

在有效质量近似下,用微扰法研究InAs量子环内类氢杂质基态及低激发态的能级.受限势采用有限深抛物型势,在二维平面极坐标下,用薛定谔方程的解析解计算.数值结果显示:在抛物势平台区,类氢杂质能级不随电子径向坐标改变,并具有二维氢原子能级的特征;在有限深抛物势区,电子能级敏感地依赖于量子环半径,能级存在极小值,这是由于限制势采用抛物势的结果.如果减小环的半径,可以增加能级间距;简并能级发生分裂并且间距随半径增大而增大,第一激发态的简并没有消除,第二激发态的简并被部分地消除.本文结果对研究量子环的光跃迁及光谱结构有指导意义.     

六参数高精度双原子分子解析势能函数

提出一种构造解析势能函数的新方法,得到一种六参数解析势能函数,该势能函数适用于多种基本类型的双原子分子.用同核中性基态双原子分子Li₂-X¹Σ_g⁺、Na₂-X¹Σ_g⁺,异核带电基态双原子分子离子(BC)^--X³∏,异核中性激发态双原子分子PbS-A¹Σ⁺、BaO-A¹Σ,异核带电激发态双原子分子离子(CS)⁺-A²∏,同核中性激发态双原子分子K₂-B¹∏_u,同核带电激发态双原子分子离子N₂⁺-B²Σ_u⁺等共36个算例对该势能函数进行验证,计算结果与RKR(Rydberg-Klein-Rees)数据或振动能谱实验数据高精度符合.同时发现,在分子振动能谱计算精度方面,该势能函数总体上优于Murrell-Sorbie势能函数.     

基态SiH~+分子离子光谱常数与振动能级研究

首先根据群论及原子分子反应静力学的相关知识,推导了SiH+分子离子基态X1Σ+的电子态和合理的离解极限。然后采用Gaussian 09程序包中优选出的QCISD(T)方法结合cc-pVQZ基组,对SiH+分子离子基态结构进行了优化计算。运用相同方法对SiH+分子离子基态进行了单点势能扫描,分别采用9参数Murrell-Sorbie函数及Murrell-Sorbie+c6函数进行了非线性最小二乘拟合,首次得到了SiH+分子离子基态的势能函数和相应的光谱常数ωe,ωexe,Be,αe。计算结果表明,利用9参数Murrell-Sorbie函数计算所得的光谱常数与实验光谱数据吻合得更好,相对误差分别为0.13%,3.07%,0.38%,5.25%以及0.52%,这些数据均说明9参数Murrell-Sorbie势能函数能更好地描述SiH+分子离子基态的性质,拟合所得势能曲线准确地再现了其离解能和平衡结构特征。通过求解双原子分子核运动的径向薛定谔方程,首次报道了SiH+分子离子基态在J=0时的振动能级、转动惯量和六个离心畸变常数。为实验上找到对应的跃迁提供了理论依据。     

VH2+分子离子的结构与势能函数

本文从VH2 分子离子基态的电子状态及其离解极限出发,采用B3PW91的方法,对V原子采用SVP基组,对H原子采用6-311 G基组优化出VH2 (X3A2)分子离子稳定构型的平衡核间距Re=0 .1631 nm,∠HVH =112 .3858°,同时计算出振动频率,并使用多体项展式理论方法,导出了基态VH2 分子离子的分析势能函数,该势能表面准确地再现了VH2 (C2v)平衡结构,然后根据势能函数等值图讨论了反应势能面的静态特征,并利用杂化轨道理论解释了VH2 分子离子的结构.     

VH_2~+分子离子的结构与势能函数

本文从VH2+分子离子基态的电子状态及其离解极限出发,采用B3PW91的方法,对V原子采用SVP基组,对H原子采用6-311 ++G基组优化出VH2+(X3A2)分子离子稳定构型的平衡核间距Re=0 .1631 nm,∠HVH =112 .3858°,同时计算出振动频率,并使用多体项展式理论方法,导出了基态VH2+分子离子的分析势能函数,该势能表面准确地再现了VH2+(C2v)平衡结构,然后根据势能函数等值图讨论了反应势能面的静态特征,并利用杂化轨道理论解释了VH2+分子离子的结构.     

基态和激发态氧振动光谱的量子力学计算

利用分子势能函数的Murrell-Sorbie和PG函数形式,将时域有限差分法应用基态和激发态氧分子的振动能级的量子力学计算,计算结果令人满意.     

Oscillator strengths of the intersubband electronic transitions in the hydrogenic nano-antidots

We calculate the oscillator strengths of the quantum antidots with hydrogenic donor impurity at the center, for transitions from the ground state to the first as well as the second excited state, in two and three dimensions, with both finite and infinite potential energy barriers. For this purpose, the binding energy spectrum and the corresponding wavefunctions, are first determined in terms of the Whittaker and the hypergeometric functions. The results are tested against the well understood limiting cases such as the free hydrogen atom in the bulk material, and also compared with the previously reported work. It is found, in particular, that the oscillator strength characterizing the transitions from the ground state to the second excited state, though negligible for small antidot radii, becomes significantly large and indeed comparable with that of the transitions to the first excited state for large enough antidot radii.     

On the Choice of the Wavefunction of the Ground State of He for Precision Calculations of Autoionization State Parameters above the Excited Ion Formation Threshold

The necessity of choosing multiparametric wavefunctions for describing the ground state of an atom in the problems of ionization of atoms by photons and electrons has been substantiated for the He atom as an example. Comparative analysis of application of different ground-state wavefunctions for this atom has been performed. The energies, widths, and partial widths of the lower autoionization state ¹P of the He atom above the excited ion formation threshold has been performed. It is shown that in contrast to total widths of quasi-stationary states, which differ insignificantly for different wavefunctions of the ground state, the partial widths are substantially different.     

Kinetic energy operator approach to the quantum three-body problem with Coulomb interactions

We present a non-variational approach to the solution of the quantum three-body problem, based on the decomposition of the three-body Laplacian operator through the use of its intrinsic symmetries. With the judicious choice of angular momentum eigenfunctions, a clean separation of spatial rotation from kinematic rotation is achieved, leading to a finite set of coupled PDEs in terms of the canonical variables. Numerical implementation of this approach to the three-body Coulomb problem is shown to yield accurate ground state eigenvalues and wavefunctions, together with those of low-lying excited states. We present results on some typical three-body systems. In particular, the eigenvalues and wavefunctions of the even-parity state of the negative hydrogen ion are detailed for the first time. The issue of computational efficiency is also briefly discussed.     

ON CALCULATION OF THE HYDROGEN NEGATIVE ION BETA SPECTRUM

The wavefunctions of the gxound states of negative hydrogen ion and the 10 first lowest ¹S states of helium atom are calculated by using a general wavefunction expansion form.The beta spectrum of the negative tritium ion is given by calculating a few most important transitions and including the remainder in terms of the closure approximation. Besides,the transition to ¹S(2S²) state is also studied.The result showed that the transition to a double-electron excited state of the helium atom may be very important. It indicates that there probably exists a resonance in the continuous spectrum.     

Dissociation of 14N2+ ions induced by slow electrons

The cross sections and thermal rate coefficients for the dissociative recombination (DR) of the molecular nitrogen ions initially in the first four vibrational levels of the ground electronic state have been computed in the framework of the multichannel quantum defect theory. An energy range of 0.001–1 eV has been considered. The contribution of the indirect DR mechanism involving Rydberg states associated with the first excited ion core has also been investigated.     

Electron-impact excitation cross sections for neon

An analytic atomic independent particle model adjusted to experimental single-particle energy levels is used to generate wavefunctions for the excited states of neon. Using these wavefunctions in conjunction with the Born approximation and the Russell-Saunders LS-coupling scheme, we calculate generalized oscillator strengths and cross sections for electron-impact excitation of neon from the 2p⁶(¹ S ₀) ground state.     

Long-range interactions of excited hydrogen atoms

Accurate calculations are reported of the first and second-order long-range interactions of a hydrogen atom in its ground state and a hydrogen atom in the excited 2s, 2p, 3s, 3p and 3d states. The connections with the spectroscopic states of molecular hydrogen are established. First-order mixing occurs for the n = 3 states and the form of the long-range interaction is complicated.     

Exact solution of coupled equations and the hyperspherical formalism: Calculation of expectation values and wavefunctions of three Coulomb-bound particles

Exact solutions of one-dimensional coupled differential equations are developed by substituting in power series. The properties of these solutions and the possibility of their application to the few-body problem in the framework of the hyperspherical method are studied. The necessity of logarithmic terms in the nonrelativistic many-body wavefunctions, as well as their absence in the relativistic case, is stressed. Explicit form of the solution of the one-dimensional hyperspherical matrix equation corresponding to the three-body Coulomb problem is found and used to obtain Schroedinger and Faddeev bound state wavefunctions, correlation integrals and probabilities of different hyperspherical states. The results of calculations with inclusion of up to 25 hyperspherical harmonics (K_m = 16) for the ground and excited state of the helium atom, the ground state of the positronium ion and the negative hydrogen ion are given and compared with those obtained by the multiconfigurational Hartree-Fock and variational methods as well as with other hyperspherical calculations. We find that generally the correlation integrals converge as the energies, that is, as $\text{1}\text{K}{}_{\mathrm{<mtext>m</mtext>}}{}^4$. While the method is essentially exact, computer round-off error limits the precision for K_m > 12 in the positronium calculations.     

Local versus hyperspherical modes of formaldehyde

Near-degenerate local versus hyperspherical modes of H₂CO are evaluated as vibrationally highly excited H₂C-stretches coupled to cold CO-bonds, for the electronic ground state (S ₀). Similar to isolated CH₂ fragments, the wavefunctions of local modes have frontier lobes pointing towards the two equivalent H·+·HCO radical product configurations. In contrast, the wavefunctions of hyperspherical modes extend approximately along arcs on spheres around the four-atom-coincidence. The wavefunctions are represented by reduced linear combinations of symmetry-adapted products of Morse times harmonic oscillator wavefunctions (LCSPM-HO). The dominant basis functions constituting the molecular vibrational states are selected by an efficient reduction technique.     

Bound states and dipole polarizability of hydrogen molecular ion H2 in weakly coupled hot plasmas

The effects of hot-dense plasmas on the bound states and the dipole polarizability of the ground state of Coulomb three-body molecular ion H⁺₂ have been investigated using highly correlated basis functions and by considering the Debye shielding approach of plasma modeling. The ground S state and the first excited P state energies along with the dipole polarizability for different shielding parameters are reported.