High-accuracy calculation of energies, lifetimes, hyperfine constants, multipole polarizabilities,and blackbody radiation shift in ~(39)K

摘要

Excitation energies of the ns, np_j, nd_nf_andng_jstates withn7in neutral potassium are evaluated.First-, second-, third-, and all-order Coulomb energies and first- and second-order Coulomb-Breit energies arecalculated. Reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined forlevels up to n=9-12. Electric-dipole (4s_(1p_j, n=4-26),electric-quadrupole (4s_(1/2)-nd_j,3-andelectric-octupole (4s_(1/2)-nf_j,n=4-26) matrix elements are calculated to obtain the ground stateE_1,E_2,andE_3static polarizabilities. Scalar and tensor polarizabilities for the 4p_jexcited state in K I are also calculated. Allthe above-mentioned matrix elements are determined using the all-order method. We also investigate thehyperfine structure in ~(39)K.The hyperfine A values are determined for the first low-lying levels up ton=7.Thequadratic Stark effect on hyperfine structure levels of the ~(39)Kground state is investigated. The calculated shiftfor the (F=2,M=0)-(F=1,M=0) transition is found to be -0.0746 Hz/ (kV/cm)~2, in agreement with theexperimental value -0.071 ± 0.002 Hz/ (kV/ cm)~2. These calculations provide a theoretical benchmark forcomparison with experiment and theory.