Stark effect, hyperfine structure and isotope shifts in highly excited states of BaI and CaI

Abstract

The electric dipole polarizabilities of 9 even-parity barium states (6s8stS0, 3S~; 6s7dlD2, 3D~,2; 5d7s ZD 2 and 6p 2 3p0,1,2) in the interval 33,800-35,800cm 1 have been measured with high resolution laser-atomic-beam spectroscopy. Simultaneously, values of isotope shifts and hyperfine coupling constants for the J= 1 states have been obtained. Comparison of the experimental polarizabilifies with calculated values as well as inspection of the data on isotope shifts and hyperfine structure from the present and earlier work strongly suggests erroneous assignments of the J--2 states, with an exception for the 5d 7s 1D 2 state.The influence of an electric field on the 3d 2 3P0,1, 2 states of calcium has also been studied. A marked departure from a quadratic Stark effect has been observed at relatively small field strengths. This can be attributed to the large polarizabilities of neighbouring Rydberg states. The low field data allow the determination of admixtures of Rydberg states into the 3d 2 3P-states as small as 0.02 %.

Theoretical isotope shifts in neutral barium

“…Finally, Wijngaarden and Li [10] (re)measured the IS of the same transition using a ring dye laser and obtained the most recent and precise IS values of this line. Many other measurements were also reported on highly excited states of Ba I [11,12].…”