engleski

THE 6s5d 1D2 → 6s5d 3DJ EXCITATION ENERGY TRANSFER IN BARIUM INDUCED BY COLLISIONS WITH He, ArAND Xe ATOMS

The cross sections for the Ba 6s5d 1D2 → 6s5d 3DJ excitation energy transfer, induced by collisions with He, Ar and Xe, were measured using laser absorption and fluorescence methods in the steady-state regime. The populations of the barium metastable 6s5d 1D2 and Ba 6s5d 3DJ states were created by subsequent radiative and collisional relaxation of the optically excited 6s6p 3P01 level. The four-level model, comprising 6s2 1S0, 6s6p 3P01, 6s5d 1D2 and 6s5d 3DJ states, is proposed for the description of the population and depopulation processes of the Ba metastable states in noble gas atmosphere. The analysis of the experimental results, within the assumed model, yields the following cross-section values for the investigated processes: σ He = 1.5 × 10− 20 m2, σ Ar = 2× 10− 22 m2 and σ Xe = 8× 10− 21 m2, with an accuracy of ± 50%.

cross section; excitation energy transfer; barium

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