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Nonsequential double ionization of diatomic molecules by elliptically polarized laser pulses 下载免费PDF全文
Using the classical ensemble method, we investigate nonsequential double ionization (NSDI) of diatomic molecules by elliptically polarized laser pulses. The results show that the ellipticity of the laser field has a strong suppression effect on NSDI probabilities both in parallel and perpendicular alignments. The double ionization (DI) channel is commonly dominated by NSDI, and the NSDI channel changes with ellipticity. As ellipticity increases, more and more NSDIs occur through recollision excitation with subsequent field ionization (RESI). Moreover, like the case of linear polarization, the two electrons involved in NSDI for perpendicularly aligned molecules are more likely to emit into the opposite hemispheres as compared to the case of parallel alignment. Additionally, this alignment effect increases as ellipticity increases. 相似文献
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Multiple recollisions in nonsequential double ionization below the recollision-ionization threshold 下载免费PDF全文
Xiao-Meng Ma 《中国物理 B》2021,30(12):123402-123402
By using the three-dimensional classical ensemble model, the recollision dynamics in nonsequential double ionization (NSDI) of Ar by 780-nm laser pulses at (6-1.2)×1014 W/cm2 was extensively studied. We revealed the picture of multiple-recollision in the double ionization events at the laser intensity region below the recollision-ionization threshold. Via tracing the NSDI trajectories, it was found that the contribution of these multiple-recollision events increases as the laser intensity decreases. In this low intensity region, many multiple-recollision induced NSDI trajectories occur through the doubly excited states. The decay speed of the doubly excited state decreases with the decreasing laser intensity. 相似文献
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We investigate the momentum and energy correlations between the two electrons from nonsequential double ionization (NSDI) of helium by strong two-color pulses with the classical three-dimensional ensemble model. The correlated momentum distribution in the direction parallel to the laser field exhibits an arc-like structure and the sum-energy spectrum shows a sharp peak for the NSDI of helium in the two-color fields. Back analysis reveals that the narrow time interval during which recollisions occur, the low returning energy and the short time delay between recollision and double ionization lead to the novel momentum and energy correlations. 相似文献
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利用三维经典系综模型研究了氢分子非次序双电离对核间距的依赖性.在不同分子取向下,氢分子双电离率随核间距的增大而先增大后减小,在核间距为4a.u.时取最大值.氢分子非次序双电离对核间距的依赖性随分子轴与激光偏振方向间夹角φ的增大而减弱.φ=0时,氢分子非次序双电离包含丰富的相关模式,对核间距有强烈的依赖性φ=π/2时,不同核间距下的相关模式相似,重碰撞在双电离过程中发挥更重要的作用.这些结果表明分子结构对双原子分子非次序双电离有重要影响.
关键词:
非次序双电离
核间距
关联动量分布 相似文献
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利用经典系综模型研究了正交双色场中氦原子非次序双电离对双色场强度比的依赖关系.研究表明, 该依赖关系与双色场相对相位φ 有关. φ =0.25π 时,沿长波长激光偏振方向的相关动量谱随强度比的增大从相关模式转变为反相关模式. φ =0.35π, 0.45π 时,相关动量主要分布在第一和第三象限,相关模式几乎不随强度比的变化而变化.对双电离轨迹碰撞时间、碰撞角、碰撞动量的向后分析可以解释上述结果,并显示了正交双色场对非次序双电离中碰撞时间、碰撞角的控制作用. 相似文献
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Using a classical ensemble method, we have investigated sequential double ionization (SDI) of Ar atoms driven by elliptical laser pulses. The results show that the ion momentum distribution of the Ar atoms depends strongly on the pulse duration. As the pulse duration increases, the ion momentum distribution changes from two bands to four bands and then to six bands and finally to an eight-band structure. Back analysis of double ionization trajectories shows that the variation of the band structure originates from pulse duration dependent multiple ionization bursts of the second electron. Our calculations indicate that the subcycle electron emission in the SDI could be more easily accessed by using elliptical laser pulses with a longer wavelength. Moreover, we show that there is good correspondence between the scaled radial momentum and the ionization time. 相似文献
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