EXPERIMENTAL INVESTIGATION OF EXCITED-STATES IN ATOMIC DYSPROSIUM

A pair of closely lying states of opposite parity and the same total e lectronic angular momentum (J = 10) at 19797.96 cm-1 in dysprosium is experimentally investigated with the goal of evaluating parameters rel evant to parity and parity-time-reversal violation experiments. An ato mic beam apparatus is used. The states of interest are populated with a sequence of two laser pulses, and a third laser pulse and fluorescen ce detection are used to probe the state population. Their lifetimes a re determined from the dependence of the fluorescence signal on the ti me delay between the pump and probe pulses. The lifetime of the even-p arity state was also measured by a different method involving detectio n of cascade fluorescence. Spectroscopy of radio-frequency E1 transiti ons between the opposite-parity states is performed when one of the st ates is populated and the population of the other is probed. This dete rmines precise energy separations between various isotope and hyperfin e structure components, and allows extraction of the corresponding iso tope shift and hyperfine structure parameters. Electric polarizability is determined from radio-frequency line shapes in the presence of a d c electric field. As part of the preparation of a parity violation exp eriment, level-crossing signals which occur when various Zeeman compon ents of the closest hyperfine components (isotope 163, F = 10.5; initi al separation 3.1 MHz) are brought together in the presence of colline ar electric and magnetic fields were studied. These measurements provi de an independent determination of the E1 matrix element between the o pposite-parity states. In addition, lifetimes, isotope, and hyperfine structure of other dysprosium states are obtained and a number of narr ow autoionization resonances (GAMMA < 10 cm-1) are observed.