Level sequence and splitting identification of closely spaced energy levels by angle-resolved analysis of fluorescence light

Abstract

The angular distribution and linear polarization of the fluorescence light following the resonant photoexcitation is investigated within the framework of the density matrix and second-order perturbation theory. Emphasis has been placed on "signatures" for determining the level sequence and splitting of intermediate (partially) overlapping resonances, if analyzed as a function of the photon energy of the incident light. Detailed computations within the multiconfiguration Dirac-Fock method have been performed especially for the 1s 2 2s 2 2p 6 3s Ji = 1/2 + γ1 → (1s 2 2s2p 6 3s)13p 3/2 J = 1/2, 3/2 → 1s 2 2s 2 2p 6 3s J f = 1/2 + γ2 photoexcitation and subsequent fluorescence emission of atomic sodium. A remarkably strong dependence of the angular distribution and linear polarization of the γ2 fluorescence emission is found upon the level sequence and splitting of the intermediate (1s 2 2s2p 6 3s)13p 3/2 J = 1/2, 3/2 overlapping resonances owing to their finite lifetime (linewidth). We therefore suggest that accurate measurements of the angular distribution and linear polarization might help identify the sequence and small splittings of closely-spaced energy levels, even if they can not be spectroscopically resolved.

Effect of molecular orbital angular momentum on spatial distribution of fluorescence during femtosecond laser filamentation in air

“…Where γ represent decay process, A 2q indicates statistical tensor calculated from density matrix, Y 2q is a spherical harmonic. In the case of 357 nm fluorescence, the initial and final states of electronic transition are φ((2σ u ) 1 (3σ g ) 2 ) and φ((2σ u ) 2 (3σ g ) 1 ) of N 2 . However, in the case of 391 nm fluorescence, the electronic transition occurs between φ((2σ u ) 1 (3σ g ) 2 ) and φ((2σ u ) 2 (3σ g ) 1 ), as well as between φ((1π u ) 3 (1π g ) 1 ) and φ((1π u ) 4 ).…”

Elastic Photon Scattering on Hydrogenic Atoms near Resonances

“…This singularity is exactly the case of the resonant intermediate state. In order to regularize the expression, we introduce the corresponding width Γ a in the denominator, i.e., we replace E a with E a − iΓ a /2 in the vicinity of the resonance [28,29]. This prescription corresponds to performing an infinite resummation of the radiative correction insertions for the resonant level [30,31].…”

Resonance strengths for KLL dielectronic recombination of highly charged mercury ions and improved empirical Z -scaling law

“…The hyperfine interaction may reduce the resulting anisotropy of DR x rays, as it was shown in Refs. [67][68][69][70], and its inclusion in the theoretical description of resonance strengths could potentially improve the agreement with the experiment. II.…”