Quantum dynamics of dissociative adsorption of H_2 and D_2:The time-dependent wave packet method

A time dependent quantum wave packet method was used to study the dynamics of dissociative adsorption of H 2 and D 2 on a flat and static surface. The molecule surface interaction is described using a modified London Eyring Polanyi Sato (LEPS) type potential for the H 2/Ni(100) system. The three dimensional (3 D) dissociation probabilities were calculated for different initial rovibrational states as a function of initial incident energies. Our results show that the dissociation of the diatomic rotational states whose quantum numbers satisfy j+m =odd is forbidden at low energies for the homonuclear H 2 and D 2 due to the selection rule. The effect of the rotational orientation of diatoms on adsorption predicts that the in plane rotation (m=j) is more favorable for dissociation than the out of plane rotation (m=0) . Enhanced dissociation for vibrationally excited molecules and the significant enhancement of the dissociation probability of H 2 when compared to D 2 were explained reasonably in terms of quantum mechanical zero point energies, the tunneling effect and the reflection from an activation barrier.

Dynamics of the Au+H2 reaction by time-dependent wave packet and quasi-classical trajectory methods

Dynamics of the Au + H2 reaction are studied using time-dependent wave packet(TDWP) and quasi-classical trajectory(QCT) methods based on a new potential energy surface [Int. J. Quantum Chem. 118 e25493(2018)]. The dynamic properties such as reaction probability, integral cross section, differential cross section and the distribution of product are studied at state-to-state level of theory. Furthermore, the present results are compared with the theoretical studies available.The results indicate that the complex-forming reaction mechanism is dominated in the reaction in the low collision energy region and the abstract reaction mechanism plays a dominant role at high collision energies. Different from previous theoretical calculations, the side-ways scattering signals are found in the present work and become more and more apparent with increasing collision energy.

Three-dimensional quantum dynamics study of vibrational predissociation of HeI_2 van der Waals molecule for low vibrational excitation using the time-dependent wave packet method

Three-dimensional quantum mechanical calculations for vibrational predissociation of HeI2(B) van der Waals molecules are presented using the time-dependent wave packet technique within the golden rule approxima tion.The total and partial decay widths,lifetimes,rates and their dependence on initial vibrational states were obtained for HeI2 at low initial vibrational excited levels.Our calculations show that the calculated tota decay widths,lifetimes and rates agree well with those extrapolated from experimental data available The predicted total decay widths as a function of initial vibrational states exhibit highly nonlinear behavior.The very short propagation time (less.than 1 ps) required in the golden rule wave packet calculation is determined by the duration time of the final state inter-action between the fragments on the vibrationally deexcited adiabatic potential surface.The final state interaction between the fragments is shown to play an important role in determining the final rotational

Variable Coefficient KdV Equation for Amplitude of Nonlinear Solitary Rossby Waves in a Sort of Time-Dependent Zonal Flow

On the basis of the quasi-geostrophic vorticity equation,theoretical research has been down upon the evolution of the amplitude of solitary Rossby waves employing the perturbation method,and come to the conclusion that the evolution of the amplitude satisfies the variable coefficient Korteweg-de Vries(KdV) equation.

Theoretical study of the influence of intense femtosecond laser field on the evolution of the wave packet and the population of NaRb molecule

Employing the two-state model and the time-dependent wave packet method, we have investigated the influences of the parameters of the intense femtosecond laser field on the evolution of the wave packet, as well as the population of ground and double-minimum electronic states of the NaRb molecule. For the different laser wavelengths, the evolution of the wave packet of 6{ }^1／Sigma ^ ＋ state with time and internuclear distance is different, and the different laser intensity brings different influences on the population of the electronic states of the NaRb molecule. One can control the evolutions of wave packet and the population in each state by varying the laser parameters appropriately, which will be a benefit for the light manipulation of atomic and molecular processes.

Influence of laser fields on the vibrational population of molecules and its wave-packet dynamical investigation

The time-dependent wave packet method is used to investigate the influence of laser-fields on the vibrational population of molecules. For a two-state system in laser fields, the populations on different vibrational levels of the upper and lower electronic states are given by wavefunctions obtained by solving the Schrbdinger equation with the split- operator method. The calculation shows that the field parameters, such as intensity, wavelength, duration, and delay time etc. can have different influences on the vibrational population. By varying the laser parameters appropriately one can control the evolution of wave packet and so the vibrational population in each state, which will benefit the light manipulation of atomic and molecular processes.

Time-dependent approach to the double-channel dissociation of the NaCs molecule induced by pulsed lasers

The dynamics of the double-channel dissociation of the NaCs molecule is investigated by using the time-dependent wave packet （TDWP） method with the ＂split operator-Fourier transform＂ scheme. At a given wavelength and intensity of laser pulse, the population of each state changing with time is obtained. The photo-absorption spectra and kinetic- energy distribution of the dissociation fragments, which exhibit vibration-level structure and dispersion of the wave packet, respectively, are also obtained. The results show that by increasing the laser intensity, one can find not only the band center shift of the photo-absorption spectrum, but also the change of the fragment energy. The appearance of the diffusive band in the photo-absorption spectrum and the multiple peaks in the kinetic-energy spectrum can be attributed to the effects of the predissoeiation limit and the external field.

Study on wave packet dynamics of E^1Σ_g^+ state of Li_2 with femtosecond-resolved photoelectron spectra

Wave packet dynamics of the Li2 molecule are investigated by using the time-dependent quantum wave packet method, and the time-resolved photoelectron spectra of the Li2 molecule are calculated. The time-resolved wave packet theory is used to reasonably interpret the phenomena of the photoelectron spectra for different parameters. Our calculation shows that the loss of the wave packets in the shelf state area of E1∑g＋ plays a prominent role in the process of photoionization with the increase of the delay time. Moreover, the oscillation of the wave packet on the E1∑g＋ curve symbolizes a decreasing process of energy.

Time-dependent theoretical approach to the influence of laser fields on the resonance enhanced multi-photon ionization of SH radical

This paper reports that the （2＋1） resonance enhanced multi-photon ionization spectra of SH radical in external fields are simulated using the split-operator scheme of time-dependent wave-packet method. Two ionic states, i.e. a1△ and b1∑＋, are involved in the simulation. It gives the simulated photoelectron spectra, the population in each electronic state, as well as the projection of the wave-packet in each electronic state on different vibrational states. These results show that the so-called four-state model can represent the experimental results well.

钢管混凝土内部孔洞缺陷监测试验

开展了钢管混凝土内部孔洞缺陷监测试验,提出了将压电材料制成埋入式压电传感器,通过布置监测系统,利用波动分析法的原理对钢管混凝土内部孔洞缺陷进行测量和分析的监测方法。设计了具有不同直径内部孔洞的钢管混凝土试件和间距不同的传感器监测组,从基于幅值和声时的时域分析角度和基于小波包能量的频域分析角度对应力波测量结果进行了对比分析。结果表明,提出的监测方法可以识别钢管混凝土内部孔洞缺陷的情况。

Time-dependent wave packet approach to the pulse delay effect upon RbI photoelectron spectrum

The time-resolved photoelectron spectrum (TRPES) of RbI molecule is simulated using the time-dependent wave-packet method. Both the normal three-photon ionization process and auto-ionization process are involved in the simulation. The calculated results show that the change of delay time will influence the shape of the photoelectron spectrum (PES), and the influence is sub- stantially due to the existence of the crossing between excited states and the strong laser field which will change the position of relevant curves.

Control of reaction channels of CsI molecule by ultra-short laser pulse

The influence of the ultra-short pulse wavelength on the populations in the three electronic states of CsI molecule is investigated using the time-dependent wave packet method. The calculated results show that the populations in the two excited states approach to the maxima at the wavelengths of 369 nm and 297 nm, respectively. The photodissociation reaction channels of the CsI molecule can be chosen by controlling the pump pulse wavelength.

D+CD_4→CD_3+D_2反应的量子含时动力学研究

运用半刚体振动转子靶 (semirigidvibratingrotortarget)模型 ,利用含时波包法 (TDWPmethod) ,对反应D +CD4→CD3 +D2 进行了量子含时动力学研究与计算。反应几率随平动能的变化图象 ,呈现出显著的量子共振特性。并通过对v =0时 ,j=0 ,1,2的反应几率以及 j=0时 ,v =0 ,1的反应几率的计算 ,对该反应的空间效应进行了研究与分析。

温度扰动激发的重力波波包非线性传播过程的数值研究

采用谱配置方法建立了一个中层大气扰动传播的全非线性动力学数值模型,利用该模型对具有高斯分布的波状温度扰动在可压大气中的演变和传播过程进行数值模拟.模拟结果表明:温度扰动很快就会激发出两支重力波波包,其中一支向上传播,而另一支则向下传播;这两支重力波波包的传播路径与线性理论给出的射线路径有些差异.进一步的数值分析则表明,给定的温度扰动在经过了约3h的演变后,完全转化为波动,在这个转化过程中,79％的扰动能量转化为波动能量.

1998年副热带高压活动与波包传播特征的研究

利用1998年5—8月NCEP/NCAR逐日再分析资料,采用波包传播的诊断方法(WPD),讨论了1998年夏季副高活动特征与500 hPa高度场瞬变波波包传播的关系,结果表明,运用瞬变波波包传播的方法来研究副高的中短期活动是基本可行的。1998年5—8月瞬变波波包大值区的向北发展和向南发展可以描述出副高脊线的南北摆动,波包小值区的向西传播和向东传播能够表示出副高脊线的西进和东退;1998年夏季副高的北跳不仅与低纬地区的波包强烈发展北传有关,同时也与中纬度西风槽槽前波包向北、向东传播或西风槽脊前波包的向南传播有关。副高脊线的南退主要与中纬度西风槽槽前的波包向南传播及其频散有关。

Manifestation of external field effect in time-resolved photo-dissociation dynamics of LiF

The photo-dissociation dynamics of LiF is investigated with newly constructed accurate ab initio potential energy curves （PECs） using the time-dependent quantum wave packet method. The oscillations and decay of the wave packet on the adiabats as a function of time are given, which can be compared with the femtosecond transition-state （FTS） spectroscopy. The photo-absorption spectra and the kinetic-energy distribution of the dissociation fragments, which can exhibit the vibration-level structure and the dispersion of the wave packet, respectively, are also obtained. The investigation shows a blue shift of the band center for the photo-absorption spectrum and multiple peaks in the kinetic-energy spectrum with increasing laser intensity, which can be attributed to external field effects. By analyzing the oscillations of the wave packet evolving on the upper adiabat, an approximate inversion scheme is devised to roughly deduce its shape.

基于嵌入压电技术的钢管核心混凝土缺陷检测

钢管混凝土构件核心混凝土缺陷影响到其延性和承载力。利用自制的嵌入式压电功能元,该文提出了基于压电陶瓷应力波测量与分析的核心混凝土缺陷监测方法。通过对比不同状态简谐激励下测量信号幅值和扫频激励下小波包能量的差异,定义了基于测量信号幅值和小波包能量的损伤指标。结果表明,利用所提出的嵌入式压电技术和所定义的损伤指标,有效地识别了钢管混凝土构件的核心混凝土损伤,损伤指标对损伤程度敏感。

基于小波分析的电压闪变信号拟同步检波的峰值比较法

提出了用小波分析的峰值比较法和拟同步检波的电压闪变信号检测新方法。该方法用软件来模拟硬件的同步检波,大大地减少了投资成本;用小波子带滤波器代替传统的低通滤波器,不仅能够对电压闪变信号进行不失真的包络检测,且能够检测出电压闪变信号发生的时间、频率以及幅值。仿真结果表明,该方法对电压闪变信号检测和时频分析性能良好,特别适用于突变的、非平稳的电压波动与闪变信号的检测。

通信系统时延抖动对基于行波法的电力线路故障定位影响分析

为研究通信系统时延抖动对基于行波法的电力线路故障定位影响,提出了一种基于泊松分布的随机时延抖动计算模型,分析了单节点和多节点情况下的通信网络随机时延抖动特性,结果表明,在单节点通信链路中,当标记数据流权重较低时,随机时延抖动随通信负荷的增大而增大,且通信负荷较轻时,标记数据流权重对随机时延抖动的影响不大。在多节点通信链路中,整体时延抖动低于各节点时延抖动的代数和,且负荷较重的节点位置对整体时延抖动有影响。因通信时延抖动会对基于行波法的电力线路故障定位引起较大误差,在通信结构和定位方案设计时,应考虑随机时延抖动及其影响因素。

D+CH_4→CH_3+HD反应的量子含时动力学研究

运用SVRT(semirigidvibratingrotortarget)模型[1 ] ,对反应D +CH4 →CH3+HD进行了量子含时动力学研究 .计算结果表明 ,反应几率随平动能的变化曲线 ,呈现出显著的量子共振特性 .H -CH3的振动激发 ,极大地提高了反应几率 ,转动量子数j的增大 ,也会使反应几率有较大的提高 .结果表明 ,SVRT模型对于精确计算某些多原子分子间的反应碰撞 。