Electric and magnetic hyperfinestructure investigations in the 5s ²5p ³ and 5s ²5p ²6s Configurations of^{121, 123}Sb

Abstract

Optical hyperfinestructure investigations in several spectral lines were carried out in the Sb-I spectrum from which for the first time accurate values of the hfs-splitting constantsA andB of the ground configuration 5p ³ and also for five of the eight levels of the first excited configuration 5p ²6s were obtained. With these parameters the influence of core polarization effects is calculated to bea _c= −6.6(4) mK, (equivalent to a magnetic field of −283(20) kG perp-electron spin). The quadrupole momentQ ₁₂₁= −0.36(4) b (including Sternheimer correction) was obtained with the experimental valuesb _3/2= −14.3(1.0) mK and 〈r ⁻³〉 =11.2(3) a.u. andQ ₁₂₃= −0.49(5) b withb _3/2= −19.9(1.0) mK resp. This evaluation also yields the relativistic correction factor η= −(C″/C′) · S _r/R′ _r=1.13(2). —For the first time, too, isotope shift investigations in Sb-I lines were possible which permit to determine the isotope shift constant βC _exp= 40(10) mK, and a value δ〈r ²〉^{121, 123}=0.12(4) fm² for the change in the mean square nuclear charge radius between¹²¹Sb and¹²³Sb which is about 50 percent of the prediction of the unified nuclear model.