Evolution of Relativistic Effects on Wigner Photoionization Time Delay of Spin-Orbit Doublets

At high Z, relativistic effects become important contributors to the quantitative and qualitative nature of atomic properties. It is important to identify and study these relativistic effects as they evolve with increasing Z to fully understand the properties. Among these properties are the Wigner photoionization time delays. A theoretical study of the spin-orbit doublet’s time delay has been performed from low Z atoms to high Z noble gas atoms to illustrate the differences in the photoionization time delays between the spin-orbit doublets as Z increases. This study was performed using the relativistic random phase approximation (RRPA) methodology [1]. It is important to note that, in the absence of relativistic effects, the time delays for the two components of the spin-orbit doublet would be exactly equal so that the differences are a sensitive measure of relativistic effects in the photoionization process. This work was supported by the US Dept. of Energy.

[1] W. R. Johnson and C. D. Lin, Phys. Rev. A 20, 964 (1979)