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1.
Using the three-state model and time-dependent wavepacket method, the influence of the parameters of the intense femtosecond laser field on the wavepacket dynamic process of the double-minimum potential state 51Σ+ and the population of the ground and diabatic electronic states of NaLi are investigated. The calculations show that different femtosecond laser parameters result in different influences on the evolution of the wavepacket and the population of NaLi. With increasing laser intensity and wavelength the diabatic coupling strength between A and B states first strengthens and then weakens. The population interchanges between A and B states when the laser pulse disappears. The above results provide the suggestions and useful information for one to achieve quantum manipulation of the molecule in an experiment. 相似文献
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Influence of laser fields on the vibrational population of molecules and its wave-packet dynamical investigation 下载免费PDF全文
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 Schro¨dinger equation with the splitoperator 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. 相似文献
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利用LAMMPS程序研究了氢原子团簇在飞秒强激光场下的动力学行为, 讨论了引起小氢原子团簇各向异性膨胀的原因.通过对外电离过程中团簇内部电子的行为以及团簇各个方向上最外层质子距离团簇中心的距离随时间的变化情况的分析, 发现团簇的膨胀呈现各向异性,且引起这种各向异性的根源在于团簇内部电子的抖动以及逃逸.对氢原子团簇与强激光场相互作用过程中质子各能量分量以及各向异性程度随时间变化情况进行了研究,发现各向异性程度是随时间变化的, 这种各向异性程度首先随着激光电场的增强而增加,随后又逐渐减小,直到最后趋于某一大于1的稳定值.分析了激光脉冲结束后质子的平均能量与观测角之间的关系, 并将分析结果与Ditmire小组的实验结果进行了比较,发现我们的模拟结果在定性上与实验相符合. 相似文献
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We experimentally demonstrate the Coulomb explosion process of CS_2 molecule under a near-infrared(800 nm)intense femtosecond laser field by a DC-sliced ion imaging technique. We obtain the DC-sliced images of these fragment ions S~+, S~(2+), CS~+, and CS~(2+)by breaking one C–S bond, and assign their Coulomb explosion channels by considering their kinetic energy release and angular distribution. We also numerically simulate the dissociation dynamics of parent ions CS_2~(k+)(k = 2–4) by a Coulomb potential approximation, and obtain the time evolution of Coulomb energy and kinetic energy release, which indicates that the dissociation time of parent ions CS_2~(k+) decreases with the increase of the charge number k.These experimental and theoretical results can serve as a useful benchmark for those researchers who work in the related area. 相似文献
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利用含时量子波包方法计算得到了Li2分子的光电子能谱,并运用波包动力学理论对含有不同参量的光电子能谱现象给出了合理的解释.通过分析文中的直观图像,研究了波包的动力学过程.结果表明,泵浦-探测脉冲的延迟时间对光电子能谱的形状有重要的影响;在较短延迟时间下,能谱独特的四峰现象是由光诱导势的产生引起的. 相似文献
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利用含时量子波包方法计算得到了Li2分子的光电子能谱,并运用波包动力学理论对含有不同参量的光电子能谱现象给出了合理的解释。通过分析文中的直观图像,研究了波包的动力学过程。结果表明,泵浦-探测脉冲的延迟时间对光电子能谱的形状有重要的影响;在较短延迟时间下,能谱独特的四峰现象是由光诱导势的产生引起的。 相似文献
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ChangZhe Zhang Bin Zheng YuQuan Niu Wei Wei QingTian Meng 《中国科学:物理学 力学 天文学(英文版)》2014,57(10):1879-1884
We investigate the photoassociation dynamics of cold NaRb molecule controlled by an asymmetric laser pulse called slowly-turned-on and rapidly-turned-off (STRT) laser pulse. This new shaped laser pulse has a remarkable merit, compared with the typical Gauss-type pulses, so that we can efficiently associate molecules with the state expected instead of going back to the continuum state. Using the three-state model, we solve the quantum mechanical equation with the “split operator-Fourier transform” method under the rotating-wave approximation (RWA) in propagation of the wave packet. By the projection of the obtained wave function onto each vibrational state, we can get the vibrational population of the ground electronic state. The results reveal that, with the STRT laser pulse, an efficient photoassociation process can be achieved and the vibrational distribution in the ground state can be controlled by the laser parameters. 相似文献
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采用含时密度泛函理论方法研究线性分子碳化锂(Li2C2)对飞秒激光场响应的电子-离子动力学行为.在典型的近共振和非共振的激光频率作用下,分别对比分析了分子的共振和非共振电离过程.研究发现:分子在共振频率激光场的作用下发生更强的电离过程,并倾向于发生库伦爆炸,键长的振荡断裂与电离相互促进影响,而分子在较弱的激光场作用下发生单光子电离过程;随着双脉冲时间间隔的增加,离化电子数在一定范围内呈振荡上升趋势,随后趋于常数. 相似文献
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采用含时密度泛函理论方法研究线性分子碳化锂(Li2C2)对飞秒激光场响应的电子-离子动力学行为。在典型的近共振和非共振的激光频率作用下,分别对比分析了分子的共振和非共振电离过程。研究发现:分子在共振频率激光场的作用下发生更强的电离过程,并倾向于发生库伦爆炸,键长的振荡断裂与电离相互促进影响,而分子在较弱的激光场作用下发生单光子电离过程;随着双脉冲时间间隔的增加,离化电子数在一定范围内呈振荡上升趋势,随后趋于常数。 相似文献
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Study on the interaction of intense femtosecond laser pulses with nanometre-sized hydrogen clusters 下载免费PDF全文
The interaction of intense femtosecond laser pulses with hydrogen clusters
has been experimentally studied. The hydrogen clusters were produced from
expansion of high-pressure hydrogen gas (backed up to 8\tm106Pa) into vacuum
through a conical nozzle cryogenically cooled by liquid nitrogen. The
average size of hydrogen clusters was estimated by Rayleigh scattering
measurement and the maximum proton energy of up to 4.2keV has been obtained
from the Coulomb explosion of hydrogen clusters under 2×1016 W/cm2 laser irradiation. Dependence of the maximum proton energy on cluster size and laser intensity was
investigated, indicating the correlation between the laser intensity and the
cluster size. The maximum proton energy is found to be directly proportional
to the laser intensity, which is consistent with the theoretical prediction. 相似文献
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利用含时波包法研究了强飞秒泵浦-探测激光场中激光脉宽对非绝热耦合NaI分子波包运动的影响.发现波包的振荡周期随脉宽增长而增大,而振荡幅度随脉宽增长而减小.非绝热效应引起的波包在交叉区域的分裂情况影响各态布居.脉宽增长,NaI分子的激发概率增大,而解离概率减小.研究表明调节激光场脉宽可实现对波包运动的控制从而控制态布居的选择性分布.研究结果可以为实验上实现分子的光控制以及量子调控过程提供一定的参考. 相似文献
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利用基于Pump-probe系统的超快时间分辨阴影图的方法,研究了空气中飞秒激光烧蚀单晶硅的动力学过程。实验采用脉宽为50 fs、平均能量密度约35 J/cm2的单脉冲激光烧蚀单晶硅,获取飞秒激光烧蚀单晶硅过程中等离子体和冲击波的形成和发展过程的时间分辨阴影图。实验结果表明:飞秒激光烧蚀单晶硅导致其表面物质喷发的过程是不连续的,分为明显的两次喷发过程。这表明飞秒激光与单晶硅作用的过程中,在不同的时间段可能由不同的机制主导,在前期可能是多光子电离为主,在后期可能是由多光子效应和雪崩效应共同作用。研究还发现,延迟时间较长时,冲击波形状发生畸变。 相似文献
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利用非波恩-奥本海默近似的三维含时量子波包法,理论研究了氢分子离子在强激光场中的解离动力学.通过分析H2+在不同的初始振动态(ν=0–9)和激光场强度下的解离核动能谱,得到了H2+的光解离机理及其随激光场的变化规律.研究结果表明:当激光场的强度I1=5.0×1013 W/cm2时,分子的解离来源于高振动态ν=5–9,其解离机理主要是通过键软化、键硬化和阈下解离过程.当激光场的强度I2=1.0×1014 W/cm2 时,H2+在低振动态ν=3–4上的阈上解离起主导作用,而高振动态的键软化、键硬化和阈下解离所占的比重明显地下降了.研究结果为后续的量子调控的实验研究提供了科学的理论预测和指导.
关键词:
光解离
氢分子离子
含时波包法
核动能谱 相似文献
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Structural deformation of nitro group of nitromethane molecule in liquid phase in an intense femtosecond laser field 下载免费PDF全文
The structural deformation of NO_2 group induced by an intense femtosecond laser field of liquid nitromethane(NM)molecule is detected by time-and frequency-resolved coherent anti-Stokes Raman spectroscopy(CARS) technique with the intense pump laser. Here, we present the mechanism of molecular alignment and deformation. The CARS spectra and its FFT spectra of liquid NM show that the NO_2 torsional mode couples with the CN symmetric stretching mode and that the NO_2 group undergoes ultrafast structural deformation with a relaxation time of 195 fs. The frequency of the NO_2 torsional mode in liquid NM(50.8±0.3 cm~(-1)) at room temperature is found. Our results prove the structural deformation of two groups in liquid NM molecule occur simultaneously in the intense laser field. 相似文献
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将伪谱方法推广应用到Kramers-Henneberger (KH) 坐标系中求解了一维原子在强激光场中的薛定谔方程,研究了强激光场中一维原子的稳定性.结果表明,在中等强度的激光场中,原子没有发生电离抑制,而在高频超强激光场中,原子的电离受到抑制. 相似文献
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Three-dimensional simulation on explosions of hydrogen atomic clusters irradiated by an intense femtosecond laser pulse 下载免费PDF全文
Using classic particle dynamics simulations, the interaction process between an intense femtosecond laser pulse and icosahedral hydrogen atomic clusters H_{13}, H_{55} and H_{147} has been studied. It is revealed that with increasing number of atoms in the cluster, the kinetic energy of ions generated in the Coulomb explosion of the ionized hydrogen clusters increases. The expansion process of the clusters after laser irradiation has also been examined, showing that the expansion scale decreases with increasing cluster size. 相似文献