共查询到20条相似文献,搜索用时 31 毫秒
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利用量子S-矩阵理论, 借助一致近似方法, 研究了波长分别为800, 1300与2000 nm的强激光场下氩原子高阶阈上电离光电子能谱的类共振增强结构. 结果表明: 在近红外和中红外波段的强激光场下, 阈上电离光电子能谱中均会出现类共振增强结构, 而出现的光强正好满足通道关闭条件, 从而进一步证实了类共振增强的通道关闭机理解释; 发现随着激光波长和光强的增加, 光电子能谱中类共振增强和抑制会交替出现, 该原因可能是电子返回次数不同的“量子轨道”间的相干叠加, 这可以解释实验观察到的长波长下出现的类共振增强能量范围展宽的现象. 研究表明, 在中红外波段的强激光场下, 也会出现与近红外波段类似的type-Ⅰ和type-Ⅱ类共振增强结构. 相似文献
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按照激光场的强度,原子与强激光场的相互作用可以大致分成几个典型区域,文章概述了不同区域内民离的基本特征和相应的理论模型,重点介绍了描述强场电离程的准静态理论,并讨论了各种理论的适用范围。 相似文献
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引入非线性空间变换,用伪谱方法求解了一维原子在强激光场中的薛定谔方程,再利用B样条函数和傅立叶级数的线性组合构造原子未微扰的本征函数,计算了一维原子在强激光场中的阈上电离谱,其结果与分裂算符法得到的结果符合得很好. 相似文献
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本文从理论上分别研究了长程和短程原子势对阈上电离光电子谱平台结构的影响. 发现在相当大的激光参数范围内, 长程势的阈上电离谱总是呈现出清晰的双平台结构; 对于短程势, 阈上电离谱双平台的界限不再清晰, 随着入射激光强度的减小, 逐渐从双平台过渡到单平台. 基于经典分析和量子力学数值模拟, 阐明了在不同模型势下, 电离速率的差别和再散射电子弹性碰撞截面的不同导致了上述平台结构的差异.此外, 还讨论了激光脉冲空间强度分布对这一现象的影响.
关键词:
阈上电离
离子势影响
中红外激光脉冲 相似文献
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ENERGETIC ABOVE-THRESHOLD IONIZATION SPECTRA OF H-ATOM IN INTENSE LASER FIELDS 总被引:2,自引:0,他引:2 下载免费PDF全文
The above-threshold ionization (ATI) spectra of H-atom in intense laser fields (laser intensity I is up to 1018W/cm2) are calculated. It is found that the kinetic energy of the ejected electron at the location of the peak of the ATI spectra is about equal to the corresponding ponderomotive potential of the applied laser fields. This result is consistent with that obtained by Wilks et al. and fits the experimental results of the super thermal electron. A possible new mechanism of the super thermal electron generation is proposed. 相似文献
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提出了描写强光场中类氢原子状态的新理论方法.同时给出强光场中类氢原子波函数的近似解析表达式.利用这个表达式通过数值计算得到的类氢原子电离谱与实验谱符合得很好.同时将这个新理论方法用于讨论高阶谐振产生也得到了满意的结果
关键词: 相似文献
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陈宝振 《原子与分子物理学报》1998,15(4):454-460
提出了一个新的处理强光中基态氦原子阈上电离谱的解析模型。由这个模型算得的基态氦原子阈上电离谱同最近的实验结果作了比较。同时简单地讨论了现在的模型对先前的模型的改进。 相似文献
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A new analytic model for the energetic above threshold ionization spectra of He is proposed. The experimental spectra by Mohideen et al. can be accurately described. The serious intensity unconsistency, which appears in the previous calculation, is actually reduced by the present calculation. 相似文献
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In order to predict the field ionization probabilities, the accurate ab initio electrostatic potential of molecules has to be calculated. However, the calculation of the full ab initio electrostatic potential of molecules is complicated, even impossible for some larger molecules with low symmetry. Here, we present a semi-empirical model to treat the field ionization of molecules in an intense laser field. In this model, a modified Coulomb potential is used to take the place of the complicated ab initio electrostatic potential of molecules. The analytic equations of the Keldysh adiabatic parameter using the Coulomb potential and the modified Coulomb potential have first been given. Using our semi-empirical model, we have calculated the field ionization probabilities and the Keldysh adiabatic parameters of O2, N2, SO2, C2H4, CH3CN and C6H6 in an intense laser field. The results agree excellently with the calculations using the ab initio electrostatic potential of molecules. As the modified parameter for the Coulomb potential can be found from experimental measurements, the field ionization mechanism of molecules can be immediately predicted with our semi-empirical model. 相似文献
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强激光场中离子HD+光解离几率的相干控制 总被引:5,自引:5,他引:0
对含时薛定谔方程用短时传播子的对称分割法求得了非微扰的数值解,计算了强超短脉冲基频激光(波长306.7nm)与其三倍频激光作用下的离子HD+光解离的相干控制参量大小设该离子的初态为电子振动.基态其中的相干激发是共振的.二束光之间的相对相位变化从0到360°在基频和倍频激光强度各为5×1013W/cm2和5.09×108W/cm2情形下,发现相对相位为π时,光解离几率达到最大。 相似文献
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A relativistic quasi-static model for the motion of the electrons in relativistic laser fields is proposed. Using the model, the recent experimental results about the generation of the hot electrons in relativistic laser fields can be fit quite well and the important role of the rescattering can be shown clearly. 相似文献