Ratios of double-to-single photoionization cross sections of helium atom embedded in dense quantum plasmas at high nonrelativistic photon energies

An investigation on the asymptotic ratios of double-to-single photoionization cross sections of the helium atom (He) embedded in dense quantum plasmas at very high nonrelativistic photon energies has been made. Exponential cosine-screened Coulomb potential has been used to represent the effective potential of a test charge in a dense quantum plasma. Making use of highly correlated wave functions for the ground states of He, results of the asymptotic ratios (R) of double-to-single photoionization cross sections for the screening parameter in the range [0,0.5] a.u. are reported. The reported value of R for the unscreened case confirms its established value. A comparative study of the behavior of R in weakly coupled plasmas and in dense quantum plasmas has also been made.