Dominance of correlation and relativistic effects on photodetachment time delay well above threshold

Wigner time delay in photodetachment from the $3{p}_{3/2}$ and $3{p}_{1/2}$ subshells of ${\mathrm{Cl}}^{\ensuremath{-}}$ has been studied in the vicinity of the $2{p}_{3/2}$ and $2{p}_{1/2}$ thresholds, using the relativistic random phase approximation (RRPA). The results show time delay spectra dominated by many-body correlations along with very complicated dependence on the energy over a broad spectral range. In addition, the time delay spectra of the two spin-orbit split $3p$ subshells differ significantly from one another, thereby revealing the importance of relativistic effects even in the case of a low-$Z$ system.