MOMENTUM-SPACE - EFFECTS OF CORRELATION IN THE DOUBLY-EXCITED STATE 2P(23)P OF HE-LIKE IONS

Momentum properties are examined for the He(2p(2) P-3)-like systems wh en 1 less than or equal to Z less than or equal to 4. Each doubly exci ted state (DES) is represented in momentum space by the Dirac-Fourier transform of the Aspromallis configuration-interaction (A-CI) wavefunc tion. Various truncations of the natural expansions of the transformed A-CI functions are used to investigate characteristics of several pro bability distribution functions and momentum expectation values. The s ensitivity of such properties with respect to the ordered introduction of Coulomb correlation effects is of particular interest. This is esp ecially so in the region of low momenta since, in position (or real) s pace, it corresponds to the outer or valence regions of an electron de nsity. Coulomb shifts, based on distribution functions for momentum di fferences, and the separate angular and radial correlation effects are analysed for each Z. Comparisons are made, in momentum space, with th e doubly occupied ground states 1s(2 1)S and, briefly for He, with the singly excited state 1s2p(2) P-3. Shapes and magnitudes of the Coulom b shifts are also related to the Coulomb holes in position space. Chan ges in statistical correlation coefficients highlight variations in th e radial and angular components of electron correlation for the 2p(2) 3P and 1s(2) S-1 states of the He-like ions as the electronic momenta decrease in magnitude.