Shifting nodal-plane suppressions in high-order-harmonic spectra from diatomic molecules in orthogonally polarized driving fields
Shifting nodal-plane suppressions in high-order-harmonic spectra from diatomic molecules in orthogonally polarized driving fields
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DOI：
10.1103/physreva.94.023406
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发表时间：
2016-02
影响因子：
2.9
通讯作者：
T. Das;C. F. D. M. Faria
中科院分区：
文献类型：
--
作者：
T. Das;C. F. D. M. Faria
我们分析了强激光场下排列的双原子分子在高次谐谱中的节面印迹，这些双原子分子的成分呈现出正交偏振。我们证明了与节面相关的光谱中典型的抑制是扭曲的，并且这种扭曲可以被用来映射电子对其母离子的返回角度。采用强场近似和最陡下降法，在单分子响应和单活性轨道水平上进行了半解析计算。我们证明了偶极算符的速度形式比长度形式更能提供有关这种失真的信息。然而，这两种形式都引入了实际动量空间波函数中不存在的伪影。此外，与双色正交场相比，椭圆偏振场导致了更大的失真。详细研究了最高占据分子轨道提供两个正交节平面的分子轨道的这些特征。
We analyze the imprint of nodal planes in high-order-harmonic spectra from aligned diatomic molecules in intense laser fields whose components exhibit orthogonal polarizations. We show that the typical suppression in the spectra associated to nodal planes is distorted, and that this distortion can be employed to map the electron's angle of return to its parent ion. This investigation is performed semianalytically at the single-molecule response and single-active orbital level, using the strong-field approximation and the steepest descent method. We show that the velocity form of the dipole operator is superior to the length form in providing information about this distortion. However, both forms introduce artifacts that are absent in the actual momentum-space wave function. Furthermore, elliptically polarized fields lead to larger distortions in comparison to two-color orthogonally polarized fields. These features are investigated in detail for ${\mathrm{O}}_{2}$, whose highest occupied molecular orbital provides two orthogonal nodal planes.