高次谐波产生的理论研究：对称性、简并度和取向的影响
Theoretical studies of high-harmonic generation: Effects of symmetry, degeneracy and orientation
摘要：
利用量子力学三步模型对四个多原子分子的高次谐波产生进行了数值计算。乙烯（C $_2$ H $_4$）用作其中轨道对称性直接影响谐波产率的实例。我们处理的情况下，甲烷（CH $_4$），以解决高谐波产生与简并轨道的分子。为此，我们说明了如何单轨道的贡献显示在总的高谐波信号。这个例子说明了从单个简并轨道相干地增加振幅贡献的重要性。最后，我们研究了丙烷（C $_3$ H $_8$）和丁烷（C $_4$ H $_{10}$）的高次谐波产生。这两个分子，被扩展和远离球形的结构，产生谐波与非平凡的取向依赖性。特别是，丙烷可以定向，使非常高的频率谐波被分解，因此该分子包含产生紫外阿秒脉冲的前景。
英文摘要：
Using a quantum mechanical three-step model we present numerical calculations on the high-harmonic generation from four polyatomic molecules. Ethylene (C$_2$H$_4$) serves as an example where orbital symmetry directly affects the harmonic yield. We treat the case of methane (CH$_4$) to address the high-harmonic generation resulting from a molecule with degenerate orbitals. To this end we illustrate how the single orbital contributions show up in the total high-harmonic signal. This example illustrates the importance of adding coherently amplitude contributions from the individual degenerate orbitals. Finally, we study the high-harmonic generation from propane (C$_3$H$_8$) and butane (C$_4$H$_{10}$). These two molecules, being extended and far from spherical in structure, produce harmonics with non-trivial orientational dependencies. In particular, propane can be oriented so that very high-frequency harmonics are favorized, and thus the molecule contains prospects for the generation of UV attosecond pulses.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
