Lifetimes of Rydberg states in ions of the group II elements

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 (0) n 3 Q l (1/n) and numerical values of the factors τ (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.