Optimal Stochastic Enhancement of Photoionization

Coherent and stochastic contributions of compound resonances in atomic processes: Electron recombination, photoionization and scattering

In open-shell atoms and ions, processes such as photoionization, combination (Raman) scattering, electron scattering and recombination, are often mediated by many-electron compound resonances. We show that their interference (neglected in the independent-resonance approximation) leads to a coherent contribution, which determines the energy-averaged total cross sections of electron- and photon-induced reactions obtained using the optical theorem. In contrast, the partial cross sections (e.g., electron recombination, or photon Raman scattering) are dominated by the stochastic contributions. Thus…

The use of relativistic action in strong-field nonlinear photoionization

Nonlinear relativistic ionization phenomena induced by a strong linearly polarized laser field are considered. The starting point is the classical relativistic action for a free electron moving in the electromagnetic field created by a strong laser beam. This action has been used to calculate semiclassical transition rates. Simple analytical expressions for the ionization rate, the photoelectron emission velocity and for the drift momentum distribution of the photoelectron have been found. The analytical formulas apply to nonrelativistic bound systems as well as to initial states with an energ…

Endohedral resonances: modification of atomic photoionization by the fullerenes shell

We discuss the complicated resonance structure of the endohedral atom photoionization cross section. Very strong enhancement and interference patterns in the photoionization cross-section of the valent and subvalent subshells of noble gas endohedral atoms A@C60 are demonstrated. It is shown also that the atomic Giant resonance can be either completely destroyed or remains almost untouched depending on the velocity of photoelectrons that are emitted in the resonance's decay process. These effects are results of dynamic modification of the incoming beam of radiation due to polarization of the fu…

On the photoionization of the outer electrons in noble gas endohedral atoms

We demonstrate the prominent modification of the outer shell photoionization cross-section in noble gas (NG) endohedral atoms NG@F under the action of the fullerene F electron shell. This shell leads to two important effects, namely to strong enhancement of the cross-section due to fullerenes shell polarization under the action of the incoming electromagnetic wave and to prominent oscillation of this cross-section due to the reflection of the photoelectron from NG by the F shell. All but He noble gas atoms are considered. The polarization of the fullerene shell is expressed via the total photo…

多共振激光同位素分离

Multi-Resonant Laser Isotope Separation

本研究提出一种基于超大体积光学腔共振增强、连续波激光原子光电离的新型同位素分离方法，效率优于现有技术，可替代放射化学并分离其无法处理的放射性同位素，对医学意义重大。

Theoretical Study of the Enhancement of Light Saturation Phenomena of Krypton at Critical Ionization Photon Energies

By calculating the correlation between the total photoionization cross-section of the ground state of the Kr atom and photon energy, three particular photon energies close to the near inner orbital energy of 1.75 keV, 1.90 keV, and 14.30 keV are determined in this work. The dynamical simulation under 17.50 keV photon energy in the experimental conditions is achieved by implementing the Monte Carlo method and optimizing the photon flux modeling parameters. As a result, our calculated data are more consistent with the experimental phenomena. The light saturation phenomenon of Kr at 1.75 keV, 1.9…

冷原子定向传播中随机共振的观测

Observation of stochastic resonance in directed propagation of cold atoms

本研究在耗散光学晶格的冷原子体系中观测到垂直于探测光方向的原子定向传播的随机共振现象，实验表征其与探测光强、晶格阱深的关系，并用模型解释了其产生机制。