The angular distributions of photoelectrons in a pump-probe scheme using linearly polarized XUV radiation for measuring the lifetime of odd singlet excited states of C III are theoretically
investigated via density matrix formalism.
The structure calculations have been performed within the
Dirac-Fock-Slater model-potential method in conjunction with the distorted wave approximation for continuum states.
General analytical expressions are provided for the angular distributions of photoelectrons in terms of statistical tensors. We show that the alignment build-up in the intermediate states drastically increases the anisotropies in the angular distributions of photoelectrons due to the fourth order Legendre polynomial contributions caused by 𝜖𝑑 electrons forming coupled states of total angular momentum 𝐽 = 2. These calculations may be useful for a better understanding of pump-probe results.