Natural radiative lifetimes in the interacting5sndD21,3

Abstract

Natural radiative lifetimes have been determined in the 5snd ' D2 sequences of strontium in the perturbed region around n =15. Stepwise laser excitations and pulse modulation of a cw dye-laser beam were employed. A plot of the measured lifetime values versus the effective quantum number reveals complex configuration interaction.

Many-body physics with alkaline-earth Rydberg lattices

“…The excitation to Rydberg states opens up several additional decay channels due to the finite radiative lifetime of the Rydberg state, off-resonant coupling to autoionizing states and direct photoionization of the Rydberg electron. The lifetime of Sr(5sns 1 S 0 ) Rydberg states due to spontaneous decay and black body radiation has been measured for low and moderate n in [36,37,30]. In order to estimate lifetimes of higher excited states we have fitted this data to the expected behaviour at large effective principal quantum numbers n ⋆ [38] …”

“…figure 1) and the spatially dependent suppression . Experimental Sr(5sns) lifetimes from [36] (triangles), [37] (dots), and [30] (squares), extrapolated to high principal quantum numbers using (10) (solid red line). The dashed and dotted blue lines shows the separate contributions of spontaneous decay and black body radiation, respectively.…”

Excitation of strontium atom in electron–atom collisions

“…All five lines turned out to be allowed transitions between terms 5s5p 3 P o -5snd 3 D for n ≥ 8 (they are shown in Italics in Table 1). The questions of perturbations of strontium-atom 3 D-levels and their possible manifestations were discussed several times [12][13][14]. It was shown experimentally [14] that the lifetime τ as a function of the principal quantum number n for the range n = 14-17 for 5snd 3 D 2 levels is not smooth because of perturbations of the 3 D-levels in this range.…”

“…The questions of perturbations of strontium-atom 3 D-levels and their possible manifestations were discussed several times [12][13][14]. It was shown experimentally [14] that the lifetime τ as a function of the principal quantum number n for the range n = 14-17 for 5snd 3 D 2 levels is not smooth because of perturbations of the 3 D-levels in this range. Because it was established earlier [15] that the functions τ = f(n) and Q = f(n) are closely related, it was expected that the behavior of the excitation cross sections for n = 14-17 would also not be smooth.…”

“…If a strictly constant quantum defect is considered one of the main criteria for the lack of a perturbation, then the examined SrI n 3 D-levels do not fully satisfy this criterion. According to the literature [17], the quantum defect of the n 3 D levels in the range n = 5-9 is not constant although its change is smooth and has comparatively narrow limits (it should be noted that n 3 D levels with only J = 2 were examined before [13,14,17]). It was noted before that one of the manifestations of a perturbation is a relative change of the branching factors [18].…”