Atomic Photoionization Dependence on the Light Polarization: Application to Hydrogenoid Atom

Abstract

The differential or total cross-sections are fundamental parameters in physics to understand the matter structure. These parameters provide relevant information on the interaction process probability. They are used in various application such as laser physics, medical radiation protection and nuclear applications. In the case of atoms or complex molecules photoionization, the analytical calculation of cross section is tedious and very complex because we have to use poly-electronic wave function. In this case it is difficult to solve the problem using the Schrodinger's equation. In order to circumvent these difficulties, we resort to mathematical approximations. This article provides a general study of the photoionization by considering atom subjected to electromagnetic radiation with photon energy close to the upper ionization threshold and using also one active electron model. A general and detailed calculation of the differential cross section as a function of photon polarization in linear case and the circular case has been performed. Moreover, we made case of an unpolarized wave and deducted the elliptical polarization component the keeping in mind that unpolarized light is mainly composed by an elliptically polarized wave. Then, a study of the angular distribution of the photoelectrons according to the \(\beta\) asymmetry parameter was made. A particular application was made on hydrogenoid atom considered as a one-electron system. From this study it appears in the vicinity of the upper photoionization threshold, the differential cross section decreases with the incident photon energy in the linear and circular polarization cases while it increases in the elliptical polarization case. So, In the linear polarization case, contrary to the circular and elliptical case, the maximum photoelectron signal (peak) is obtained witch the ejection photoelectron angle \(\theta = 0\) (forwards ejection electron) or \(\theta = \pi\) (backscattering).