Ab initio study of high-lying doubly excited states of helium in static electric fields: Complex-scaling generalized pseudospectral method in hyperspherical coordinates

摘要

We present a complex-scaling(CS) generalized pseudospectral(GPS) method in hyperspherical coordinates(HSC) for ab initio and accurate treatment of the resonance energies and autoionization widths of two-electron atomic systems in the presence of a strong dc electric field. The GPS method allows nonuniform and optimal spatial discretization of the two-electron Hamiltonian in HSC with the use of only a modest number of grid points. The procedure is applied for the first precision calculation of the energies and autoionization widths for the high-lying 1Se, 1Po, 1De, and 1Fo(n=10-20) doubly excited resonance states of He atoms. In addition, we present a theoretical prediction of the energies and widths of high-lying doubly excited resonance states of 1Po(n= 8-15) in external dc electric field strengths of 3.915-10.44 kV/cm. The calculated dc-field perturbed high-lying resonance energies are in good agreement with the latest experimental data.