Large Electric Polarizability of 6s5d1D2–5d6p1D2 Transition in Ba.

Measurement of the Stark effect of the 856-nm transition from the 6s5d¹D₂ metastable state to the 5d6p¹D₂ level in Ba is reported. High-resolution atomic-beam laser spectroscopy was performed and Stark shifts and splittings of ¹³⁸Ba and ¹³⁶Ba were measured under various electric fields. The tensor polarizability of the upper level 5d6p¹D₂ and scalar polarizability of the 6s5d¹D₂–5d6p¹D₂ transition were found to be much larger than those of other levels of the 5d6p configuration. The observed large electric polarizabilities were reasonable compared with recent results on the related forbidden transition of 6s5d¹D₂–5d²¹D₂, which further indicates strong mixing between the upper close-lying levels of 5d6p¹D₂ and 5d²¹D₂. [ABSTRACT FROM AUTHOR]