Na2分子部分电子态的完全振动能谱和离解能的精确研究

对于大多数双原子分子的电子态，用现代实验方法或精确的量子理论方法往往可以获得含m个振动能级的能谱子集合［Ev］，而不易得到包含最高振动能级在内的所有高振动量子态能级的完全振动能谱{Ev}.鉴于Na2分子电子态的振动能谱和分子离解能De在实际研究和应用中的重要性，使用基于微扰理论的代数方法（AM），获得了Na2分子一些电子态的振动光谱常数和完全振动能谱；使用基于AM的代数能量方法（AEM）获得了这些电子态的正确离解能.研究结果表明：AM方法能从少数精确的实验能级获得精确的分子振动光谱常数集合和正确的完全振动能谱{Ev}，AEM方法获得的分子离解能比由文献发表的振动光谱常数计算得到的近似离解能值更准确，对于难以获得分子离解能的那些电子激发态，AEM方法能给出合理的离解能数据. 关键词： Na2分子 代数方法 振动能级 离解能 电子激发态     

Realization of Nonclassical States and Two-Mode Coupling in the Motion of Two Trapped Ions

We propose a scheme to generate various nonclassical vibrational states in the collective motion of two trapped ions, such as squeezed states, Schrödinger cat states, and SU(2) states. It is based on Raman-type excitations. Two-mode coupling between the center-of-mass and relative vibrational modes can also be realized.     

Comparison of Raman spectra and vibrational density of states between graphene nanoribbons with different edges

Vibrational properties of graphene nanoribbons are examined with density functional based tight-binding method and non-resonant bond polarization theory. We show that the recently discovered reconstructed zigzag edge can be identified from the emergence of high-energy vibrational mode due to strong triple bonds at the edges. This mode is visible also in the Raman spectrum. Total vibrational density of states of the reconstructed zigzag edge is observed to resemble the vibrational density of states of armchair, rather than zigzag, graphene nanoribbon. Edge-related vibrational states increase in energy which corroborates increased rigidity of the reconstructed zigzag edge.     

Measurement of the Wigner Characteristic Function for the Center－of－Mass Motion of Two Trapped Ions

We proposed a scheme for the reconstruction of the quantum states for the center-of-mass vibrational mode of two trapped ions. In the scheme the ions are multichromatically excited by three lasers. Then measurement of the difference between probabilities of the ions being both in electronic ground and excited states directly yields the Wigner characteristic function for the center-of-mass vibrational state. The scheme can also be used to prepare entangled coherent states for the center-of-mass and relative vibrational modes.     

Effect of squeezed vibrational states on the optical properties of molecular systems in a field of laser radiation

Specific features of optical and nonradiative transitions in molecular systems in the field of an intense electromagnetic wave are studied with account of squeezed vibrational states. It is shown that a field of laser radiation considerably enhances the tunneling processes in electronic vibrational systems and makes it possible to obtain the generation of higher harmonics. Conditions are found under which squeezed vibrational states can lead to some stabilization of excited electronic states with respect to the processes of luminescence.     

一维准晶链晶格振动的进一步研究

本文研究了一维准晶链晶格振动,特别是临界态的振动特性,给出了对不同振动态的几种描述方法。     

氢分子离子库仑爆炸中核动力学的理论研究

在非Born-Oppenheimer近似条件下, 通过数值求解一维含时薛定谔方程, 理论模拟了氢分子离子处于不同初始核振动态的库仑爆炸核动能释放谱并探究了氢分子离子发生库仑爆炸时的核动力学. 数值结果表明: 初始核振动态的选取在很大程度上影响着氢分子离子发生库仑爆炸时的核动力学,且高低振动态的选取分别对其核动力学的影响呈现出相反的变化趋势.     

用代数能量方法研究氢化物双原子分子的完全振动能谱和离解能

本文用研究双原子分子振动能谱的新方法-代数方法(AM),研究了KH-X1Σ+,RbH-X1Σ+,DF-X1Σ+和DCl-X1Σ+等四个氢化物双原子分子的电子基态的振动光谱常数和振动能谱;用代数能量方法(AEM)研究了相应电子态的分子离解能.研究结果表明:使用实验获得的少数精确的振动能级[Eυ],由AM方法得到的振动能谱不仅能够重复这些电子态的已知实验能级,还能够得到用现代实验方法或精确的量子理论方法很难得到的所有高振动激发态的能级.由AEM方法能够得到比用文献发表的振动光谱常数计算获得的离解能值更准确的分子离解能.     

Submillimeter-wave spectroscopy of HCN in excited vibrational states

Measurements of the rotational spectrum of HCN in excited vibrational states have been extended to higher-J values. The transitions reach J=8←7 around 710 GHz for most vibrational states studied in this investigation and J=22←21 near 2 THz for the (020) and (030) vibrational states. Using a pure sample of gaseous HCN at 350 K, selected states up to one quantum in the C–H stretching vibration at 3311.5 cm⁻¹ have been investigated. Even transitions having two quanta in the C–H stretch could be studied employing a glow discharge in a gas mixture of CH₄ and N₂. Molecular constants in 13 vibrational states have been obtained, several of which have been studied for the first time by rotational spectroscopy. The vibrational temperature in the discharge system is found to be about 1500 K for the stretching vibrational modes and about 600 K for the bending states.     

Storage of Entangled States with Multiple Trapped Ions in Thermal Motion

This paper presents an alternative scheme to realize the storage of entangled states for multiple trapped ions including W state, Bell states, and GHZ states even with ions which exchange vibrational energy with a heating surrounding. Our scheme requires that the ions be simultaneously excited by two laser beams with different frequencies.In this scheme the vibrational degrees of freedom are only regarded as intermediate states and the ions exchange energy via the mediation of the vibration of the vibrational mode in coupling processes. The scheme is insensitive to both the initial vibrational state and heating if the system remains in the Lamb-Dicke regime. Since the effective Rabi frequency has a small dependence on the vibrational quantum number the heating will have no direct effect on the internal state evolution.     

一维准晶链晶格振动的进一步研究

本文研究了一维准晶链晶格振动, 特别是临界态的振动特性, 给出了对不同振动态的几种描述方法. 关键词：     

Impact of the Vibrationally Excited States on the Macroscopic Behaviour of the Band-like Electron Beam Discharge Plasma in H/H2-Mixture

The investigation of the impact of the vibrationally excited molecules in the electronic ground state was performed by simultaneously solving a balance equation system for the main charge carriers, the H atoms, the metastable H atoms, the H₂ molecules in the different vibrational states and for the power transfer of the electrons in the beam discharge mixture plasma. The balance equations for the vibrational states include in particular one-quantum step excitation and deexcitation, electronic excitation, dissociation and ionization from each vibrational level in electron collisions as well as the finite life time of these states because of the gas transfer through the band-like plasma. A main finding is that due to the additional impact of vibrationally excited molecules there is a marked enhancement of the resulting dissociation and ionization degree in the beam discharge plasma at medium power input from the turbulent electric field. For discharge parameters of practical interest the ionization and dissociation budget, the population of the vibrational states, the different energy dissipation processes and the energy pumping into the ladder of the vibrational states were calculated and discussed in detail.     

用差分收敛法研究NaLi分子部分电子态的完全振动能谱

基于双核分子振动能级的普遍表达式和差分收敛法(difference converging method, DCM), 利用微分思想将DCM应用于双核分子体系完全振动能谱的研究中. 应用DCM方法, 分别选用实验上获得的一组(10条)精确的振动能级, 对NaLi分子3¹Π, 4¹Π 和A¹Σ⁺电子态进行了研究, DCM的研究结果正确重复了已知数据并预测出了在实验上未能获得的包含高激发态在内的完全振动能谱数据, 同时计算得到了这3个电子态的振动光谱常数.     

分子高激发振动态的理论研究

简要综述了分子高激发振动态的理论研究方法和研究进展.介绍了李代数方法在高激发振动态能级的归属和分类、分子高激发振动态动力学以及分子内振动能量弛豫和分子解离等方面的应用.随后,作者对分子高激发振动态研究领域今后的发展方向作了展望.     

Preparation of nonclassical states and measurement of the Wigner function for the collective motion of N trapped ions

We propose a scheme for generating nonclassical states for the centre-of-mass vibrational mode of N trapped ions,including superpositions of several coherent states on a circle and Fock states. In the scheme N trapped ions are driven by a laser beam tuned to the carrier. The scheme also provides a new prospect for laser cooling. The scheme can be used to measure the Wigner function of the collective vibrational mode.     

Simulation of vibrational spectra of SiO2 nanoclusters

The vibrational density of states of α-SiO₂ nanoclusters with different diameters has been calculated in terms of the shell model in the harmonic approximation. A decrease in the diameter of nanoparticles leads to an increase in the vibrational density of states in the low-frequency range of the spectrum, a shift of the spectrum in the high-frequency range, and the generation of gap vibrational modes. The interpretation of the observed features has been proposed.     

Optical control of the quantum-state distribution of vibrational wave packets using trains of phase-locked pulses

An intuitive scheme for controlling the quantum state composition of one-coordinate molecular wave packets is developed. The accumulated phase difference between the various components of the molecular wave packet is determined, and then a sequence of phase-locked optical pulses is employed to selectively enhance or depopulate specific vibrational states, or sets of vibrational states. The quantum state composition of the resulting wave packet, and the efficiency of the control scheme, is determined by calculating the multi-pulse response of the time-dependent vibrational state populations.     

Theory of pressure-induced vibrational and rotational absorption of diatomic molecules at high temperatures

A derivation is given for the integrated absorption coefficient of pressure-induced pure rotational and vibrational transitions in binary collisions of homonuclear diatomic molecules of the same chemical species. The previously neglected effects of excited vibrational states, mechanical anharmonicity, and vibration-rotation interaction are taken into account to obtain more accurate absorption coefficients at high temperatures. In the region of the fundamental wave number the excited vibrational states make more of a contribution to the absorption than their relative population would lead one to expect.