As Single photoionization cross section is very sensitive to the wave functions used in the matrix elements and hence
provides an opportunity to test the accuracy of wave functions. So to test the accuracy of our configuration-interaction (CI) wave
functions which have already produced reliable oscillator strengths , we have performed calculations for the single
photoionization cross sections (SPICS) of alkali metal atom Beryllium [Be(1s2
2s2
)] employing configuration interaction (CI)
wave function for the ground state and Coulomb wave function for the final state. Our present results length and velocity forms
are closer than other theoretical results but there is discrepancy between experimental and present theoretical results near
threshold to intermediate energy regions which suggests to do further investigation. Our present results suggest that full
configuration interaction wave functions must be used in the R-matrix as well as RR-matrix in order to obtain high precision
results.
