Hyperfine Interaction, Zeeman and Stark Effects for Excited States in Potassium

Abstract

Using the optical double resonance and level crossing methods, properties of several excited S, P, and D states in 39K were studied. The S and D states were populated using stepwise excitation with the first P state as an intermediate level. An rf lamp and a CW dye laser were used in the first and second excitation steps, respectively. The studied P states were populated in the cascade decay of states, excited with the laser. The following results for the magnetic depole interaction constant a, the Landé gJ factor, and the tensor polarizability α2 were obtained for the studied states:7 2S1/2: a = 10.78(5) MHz, gJ = 2.0020(10);8 2S1/2: a = 5.99(8) MHz, gJ = 2.0028(12);6 2P1/2: a = 4.05(7) MHz, gJ = 0.6663(4);6 2P3/2: a = 0.89(5) MHz, gJ = 1.3337(8);7 2P1/2: a = 2.18(5) MHz, gJ = 0.6659(6);7 2P3/2: a = 0.49(4) MHz, gJ = 1.3336(8);5 2D3/2: |a| = 0.44(10) MHz, gJ = 0.7997(7), |α2| = 9.64(45) MHz/(kV)/cm)2;5 2D5/2: |a| = 0.24(7) MHz, gJ = 1.2004(10), |α2| = 13.4(7) MHz/(kV)/cm)2;6 2D3/2: |a| = 0.2(2) MHz, gJ = 0.7997(14), |α2| = 33.8(1.7) MHz/(kV)/cm)2;6 2D5/2: |a| = 0.1(1) MHz, gJ = 1.2013(20), |α2| = 47.6(2.4) MHz/(kV)/cm)2.Theoretical values for the magnetic dipole interaction constant have been obtained using a limited many-body perturbation expansion. The Polarization effect, which is due to single excitations from the restricted Hartree-Fock model, is included to all orders, while the true correlation effect is omitted. The results are compared with the experimental values, and the agreement is found to be quite good. For the S and P states the polarization effect is of the order of 10-20%, and it is responsible for roughly half of the deviation of the Hartree-Fock values from experiment. For the D states, on the other hand, the effects are much more drastic. The sign of the a factors has not been measured. The perturbative calculation yields positive values for all 2D3/2 states and negative values for all 2D5/2 states. The theoretical magnitudes are in agreement with the observed ones.