The high-order harmonic generation (HHG) in xenon is studied by using the time-dependent density-functional theory. The dynamics of all electrons on the outer 4th and 5th atomic shells is considered with subsequent separation of contributions of different atomic orbitals to the HHG amplitude. It is shown that giant enhancement of HHG yield in a spectral region near 100eV is caused by perturbation of the electron–electron interaction potential induced by recolliding photoelectron wavepacket originated from the 5p ₀ orbital. This perturbation leads to the collective oscillations of all orbitals on the 4th shell closely localized in space and strongly interacting with each other. The resulting HHG yield is enhanced by more than an order of magnitude compared with the response of the single 5p ₀ orbital. The high accuracy of the numerical results is confirmed by comparing the calculated HHG spectra and photoionization cross-sections with experimental results and an analytical parameterization of the HHG yield.

利用瞬态密度泛函理论研究了氙气中的高次谐波产生 (HHG)。考虑了外层第 4 和第 5 原子壳上所有电子的动力学，随后分离了不同原子轨道对 HHG 振幅的贡献。结果表明，在接近 100eV 的光谱区域内，HHG 产率的巨大增强是由源自 5 p ₀轨道的光电子波包重新碰撞引起的电子-电子相互作用势的扰动引起的。这种扰动导致第 4 壳层上所有轨道的集体振荡，它们紧密地定位在空间中并相互强烈相互作用。与单个 5p ₀轨道。通过将计算的 HHG 光谱和光电离截面与实验结果和 HHG 产率的分析参数化进行比较，证实了数值结果的高精度。