Population Kinetics of Excited States

Iu. A. Kulagin, Leonid A. Shelepin

Yu. A. Kulagin, Leonid A. Shelepin

M. B. Gornyi, Boris G. Matisov

Harm Geert Muller, M. P. de Boer

M. L. Yanson, V. B. Grushevskii, P. Klyavinsh

This study carries out an experimental investigation of the radiative decay kinetics of the resonance states of sodium atoms excited by dye laser radiation. The effective radiative decay rates of the resonance states as a function of vapor temperature, primary and impurity gas presssure, and the radius of the cylindrical volume containing the vapor were obtained by computer processing ofthe experimental curves using a kinetic decay model.-The radiative decay rate calculated in the Holstein approximation is compared to the measured values. The mechanisms of optical excitation of metallic vapors in resonance radiation trapping conditions have been investigated theoretically to a sufficient degree.lr At the same time there have been few experimental studies devoted to this problem. The decay kinetics of the atomic resonance states in the vapors of alkali metals have largely been studied for a planar radiating layer,2-6 where the nonideal geometry of the radiating volume made it necessary to introduce a fitting parameter to compare the experimental results to theory. The radiative decay kinetics of the populations of the resonance 3P states of atomic Na under conditions of axial laser excitation of a cylindrical shell are investigated in the present paper for the first time; this made it possible to carry out a comparison to theory without introducing variable parameters, since in this case exact analytic expressions are known for the effective lifetimes. It should also be emphasized that cylindrically configured cells are most commonly used in experimental research and hence these results have a certain interest in such studies. For our analysis we selected a concentration range of normal sodium atoms of 3 X 1013 <;no<;4 X 1015 cm - where selective optical excitation of the fine structure components (FSC) 32Pl/2 and 32P3/2 are accompanied by collisional mixing, which has a substantial effect on the persistence kinetics of the NaD lines. Under these conditions the decay of the directly excited fine structure component is biexponential, while the time dependence of the population of the corresponding level takes the form

Zhigang Zheng, Di Wang, Ming-Yue Wang +6 more

Abstract This letter demonstrates an experimental approach to measuring the angular-momentum-resolved population of excited states in laser-produced argon ions. By measuring the spectra of free induction decay emissions corresponding to the resonant transitions between Rydberg states, the relative population of the Rydberg states is obtained with known Einstein A-coefficients. This study deepens the mechanistic understanding of coherent dynamics in laser-driven ionic excited states, and establishes experimental benchmarks essential for validating and refining advanced quantum kinetic models in strong-field physics.