Lifetimes of Rydberg States in Ions of the Group II Elements

摘要

Total probabilities A_(nl) of spontaneous radiative transitions, which determine lifetimes τ_(nl) = 1/A_(nl) of nS-, nP-, nD- and nF-states in singly charged ions of the group IIa (Be~+, Mg~+, Ca~+, Sr~+, Ba~+) and IIb (Zn~+, Cd~+, Hg~+) elements, were calculated in the single-electron Fues' model potential (FMP) method. An asymptotic dependence is determined for highly excited states with small angular momentums and presented in the form τ_(nl) = τ_l~(0)n~3Q_l(1) and numerical values of the factors τ_l~(0) and coefficients of the cubic polynomial Q_l(x) are calculated, which approximate results of numerical computations with relative error below 2% in the range of states with principal quantum numbers from n = 7 to n ≈ 2000. The comparison of the numerical results with data in literature is presented, and applicability and reliability of single-electron model calculations are discussed in detail for positive singly charged ions of the group II elements.