MCHF calculations of electric dipole and quadrupole oscillator strengths along the helium isoelectronic sequence

Abstract

Accurate wavefunctions obtained by the MCHF method in its reduced form were used to compute the oscillator strengths for all possible electric dipole (E1) and electric quadrupole (E2) transitions between the states 11S, 21,3(S,P0), 31,3D and 41,3F0 of helium-like systems ranging from He I to Ne IX. The length and velocity forms of the oscillator strengths are in close agreement in all cases; the correlation contributions to the gf values are discussed. The present results are the most accurate to date for E11,3(3D-4F0) and for all the E2 transitions.