5p−4f level crossing in palladium-like ions and its effect on metastable states

Hyperfine-structure-resolved laser spectroscopy of many-electron highly charged ions

“…We controllably maintained the EBIT electron density below 10 10 cm −3 , where the total collisional excitation and de-excitation rate out of the (4d 9 3=2 5s) J=2 level was approximately 10 3 s −1 (see ref. 49 ). The production rate of (4d 9 5=2 5s) J=3 under an electron density of 10 10 cm −3 was estimated to be ~160 s −1 from collisional-radiative modeling 49 .…”

Hyperfine-structure-resolved laser spectroscopy of many-electron highly charged ions

“…We controllably maintained the EBIT electron density below 10 10 cm −1 , where the electron collision rate was apporoximately 10 3 s −1 . The production rate of (4d 9 5/2 5s) J=3 under an electron density of 10 10 cm −1 was estimated to be ∼160 s −1 from collisionalradiative modeling [44]. Thus, the excitation rate by the pulse laser was operated at less than 1 s −1 avoiding the depletion of the population in the initial state (4d 9 5/2 5s) J=3 .…”

“…F =11/2 + 2.6 cm -1 + 0.7 cm -1 -0.9 cm -1 -2.1 cm -1 -2.9 cm -1 -3.6 cm -1 + 2.6 cm -1 + 0.2 cm -1 -1. . The population rate to (4d 9 5/2 5s)J=3 was estimated, using collisionalradiative modeling [44]. An electron energy of 105 eV and a density of 10 10 cm −3 are assumed in the collisionalradiative rates, corresponding to the present experimental condition.…”

“…Figure 3 shows the LIF detection in the present experimental setup. From CH 3 I vapor, 127 I 7+ ions were produced by an electron beam and stored in an electrostatic trap potential formed by the electron beam and three successive cylindrical drift-tube (DT) electrodes [44]. To excite the M 1 transitions, we used a wavelengthtunable dye laser (Sirah Cobra-Stretch with the dual 3000 lines/mm grating option, Exciton Rhodamine 6G/ Ethanol dye solution) pumped by the second harmonic of an Nd:YAG nanosecond-pulse laser (Cutting Edge Optics Gigashot, 10 ns) with a 100 Hz repetition rate.…”

New Horizons: Scalar and Vector Ultralight Dark Matter

“…Many isoelectronic sequences have such states, and forbidden transitions from magnetic-dipole (M1) type are well known in the optical and ultraviolet range (see references in [346]), even up to charge states as high as Bi 82+ and other hydrogen-like systems [347][348][349][350][351][352] which were already identified as appropriate for use in searches for a temporal variation of α [345,353,354]. For these reasons, many proposals for HCI clocks with high sensitivity to a change in α have been made [316,336,[355][356][357][358][359][360][361][362][363][364][365][366][367], and several experimental groups are searching for them using both electron beam ion traps (see references cited in [320]), Penning traps [368] and Paul traps [321]. Searching for fifth forces by studying the g factor of electrons bound in HCIs has also been suggested [369].…”