ANISOTROPIC INTERACTIONS IN AUTOIONIZING RYDBERG SYSTEMS

We present an improved theoretical description of Rydberg electron mot ion in the presence of an arbitrary ionic core. Through the use of a g eneralized eigenvalue equation involving Coulomb, multipole, and polar iza tion interactions we are able to describe accurately the physics o f the autoionizing Mg 3pnf Rydberg states. The vector hyperpolarizabil ity beta(v), the proportionality constant for an interaction term with the operator structure <(L)over right arrow (c)>.<(l)over right arrow /r(6)>, where <(L)over right arrow (c)> and (l) over right arrow are the orbital momenta of the ionic core and the Rydberg electron, is fou nd to be 1.885 a.u., roughly two orders of magnitude larger than in gr ound-state Ne+. The effects of nonadiabatic radial interactions now em erge clearly. Comparisons with measured autoionization energies and ra tes, and with those computed using R-matrix and multichannel quantum d efect theory methods, confirm the accuracy of this approach; The conce pt of adiabatic torquing of orbital planes is introduced and explored in Rydberg magnesium.