Calculation of autoionization widths for two-electron systems

Observation of the partial decay intoH0(n’=2) by excitedH−Halka1, Bryant2, MacKerrow3 et al. 1991Phys. Rev. A395190View full textAdd to dashboardCite

“…Feshbach peak whose energy is weI1 known from experiment [11]. Since it is effectively a delta function (30 peV) [12], its observed width demonstrated our energy resolution of 0.007 eV.…”

“…We have made the first step toward a quantitative study of these ratios by observing the cross section for both the H *'(3) and H "(4) decaying into H (2) as depicted in Figs. 1 [16], 12.6470 [20] 0.0325 [17], 0.0316 [18], 0.0325 [20] 13.3448 [14], 13.3502 [15], 13.3435 [16], 13.3422 [21] 0.0275 [18], 0.0339 [19], 0.0367 [21] 12. Feshbach peak whose energy is weI1 known from experiment [11].…”

Observation of the (2p,nd)1Podouble-excitation Ry

“…1 contains also weak lines from the autoionization decay of the (sp,2n -) states, which were previously observed up to n -1 only [8], but are now identified up to n = 11. The (sp,2n -) states are at lower energies than the respective (sp,2n + ) states and are observed with =75 times smaller spectral intensities due to their much narrower lifetime widths [1,8,12]. The lowest six of the (sp,2n -) resonances are shown in more detail in Fig.…”

“…In photoexcitation, the dipole-selection rule allows only X P° final states, which reduces the number of observable Rydberg series to three [10]: Only two of them, the (sp,2n + ) x P° and the (sp,2n~) x P° series could be observed until now [3,8], while the third (2p,nd) l P° series was missing [11]. This situation has led to considerable confusion, since the various theoretical calculations are characterized by substantial discrepancies with respect to the energies and widths of the (2p,nd) ] P° states [5][6][7][11][12][13][14][15].In the present Letter we report on the first observation of the four lowest states of the (2p,nd) ] P° series by high-resolution photoabsorption spectroscopy using synchrotron radiation. With a resolving power of E/AE = 16000 combined with high photon flux, the (sp, 2n + ) x P° and (sp,2n -) l P° series were in addition resolved up to the n =20 and the n = 11 state, respectively.…”

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

“…Throughout this paper, we use the (N,n, (a,b, or c)) representation for doubly excited states introduced by Lipsky and Conneely [35], which is widely used for He. We expect our results will stimulate further experimental works in the future.…”