Haruko Uematsu

High-Resolution Diode-Laser Spectroscopy of the Rare-Earth Elements

High-resolution laser spectroscopy has been performed for the rare-earth elements as well as Ba by using a tunable diode laser together with a well collimated atomic beam. Hyperfine structures and isotope shifts have been measured for eight transitions in Ba I, Ce I, Sm I, Eu I, Gd I and Yb I. Hyperfine constants A and B have been determined for the 4 f 7 5 d 6 s 6 p 11 F 5 level of 155,157 Gd, and the 4 f 14 6 s 6 p 3 P 2 , 4 f 14 6 s 7 s 3 S 1 levels of 171,173 Yb. The field shifts and 6 s -electron densities at the nucleus have been derived for the studied elements and compared with the Hartree–Fock calculation.

Specific Mass Shift in Gd I and Dy I

High-resolution diode-laser spectroscopy has been performed on atomic beams of natural Gd and Dy. Isotope shifts of the even-mass isotopes have been measured for two transitions in Gd I and one transition in Dy I. Specific mass shifts, as well as field shifts, have been derived for transitions of 4 f 7 5 d 6 s 2 –4 f 7 6 s 2 6 p in Gd I, and 4 f 10 6 s 2 –4 f 9 5 d 6 s 2 in Dy I; the specific mass shift is much larger than the normal mass shift. It has been found that the specific mass shift of the 4 f 10 6 s 2 –4 f 9 5 d 6 s 2 transition in Dy I is about one order of magnitude larger than that of the 4 f 7 5 d 6 s 2 –4 f 7 6 s 2 6 p transition in Gd I. This shows that the specific mass shift, related to the correlation effect between electrons, strongly depends on the orbital angular momentum of electrons.

Atomic Beam Diode-Laser Spectroscopy

Combined with a collimated atomic beam source, diode laser without external cavity has been used as a spectroscopic light source to study atomic hyperfine structures and isotope shifts of Ba i. Spectroscopic measurements of the 6s21S0 – 6s6p3P1 transition of Ba i have been carried out. All hyperfine peaks of 135,137Ba have been clearly seen and resolution of 50 MHz has been attained. Hyperfine constants A and B of the 3P1 state of 135,137Ba have been determined. Isotope shifts of stable Ba isotopes have also been measured. From the measured isotope shifts, the 6s electron density at the nucleus has been deduced to be 76.4(53) a.u. and discussed in terms of the Hartree-Fock approximation.

Initial phase of laser-induced air optical breakdown: a new picture

Optical breakdown has been generated by focusing YAG laser radiation in the air. The laser radiation itself was scattered due to laser-induced air optical breakdown. Angular distributions of scattered radiation at 1064, 532, and 355 nm were measured. Analysis of the distributions has been performed in terms of Mie scattering. It has been assumed that scattering of laser radiation is due mainly to highly ionized plasma balls in the initial phase of air optical breakdown. The wavelength-dependent angular distribution has been analyzed with two parameters. The mean radius and the plasma frequency of the plasma balls have been determined by a least-squares fit procedure. Observed wavelength-dependent angular distributions are in good agreement with ones calculated by Mie theory.

Hyperfine Structure of 27Al by High-Resolution Ultraviolet Laser Spectroscopy

The high-resolution ultraviolet (UV) laser spectroscopy of 27Al has been performed by the frequency doubling of a tunable diode-laser beam together with a collimated atomic beam. Hyperfine structure spectra have been observed for two UV transitions in Al I, namely, 3s23 p2P1/2–3s24s2S1/2 at 394.401 nm and 3s23 p2P3/2–3s24s2S1/2 at 396.152 nm. The hyperfine structure constants A and B of 27Al have been determined for the 3s23 p2P1/2,3/2 and 3s24s2S1/2 levels, and compared with previously reported results.

J Dependence of the Isotope Shift in the Gd I 4f76s26p9P Term

High-resolution laser spectroscopy in Gd I has been performed using a tunable diode laser. Isotope shifts of the even-mass isotopes have been measured for two transitions from the 4f75d6s29D4 and 9D5 levels to the 4f76s26p9P3 and 9P4 levels in Gd I. The J dependence of the isotope shift, related to the crossed-second-order (CSO) effect, has been obtained for the 4f76s26p9P3 and 9P4 levels. The CSO parameter z6p of the 4f76s26p configuration has been estimated for the first time.

Measurements of the Hyperfine Structure and ΔF = +2 Transitions in Eu I by High-Resolution Diode-Laser Spectroscopy

High-resolution atomic-beam laser spectroscopy in Eu I has been performed using a tunable diode laser. The hyperfine structure (hfs) and isotope shift of the 4f 6s S7=2–4f 6s6p P9=2 transition at 686.45 nm have been measured. The hfs constants A and B of Eu and Eu have been determined for the upper state 4f 6s6p P9=2, and the hyperfine anomaly has been derived. The F 1⁄4 þ2 transitions, normally forbidden, have been induced by applying a magnetic field of approximately 1G. Their intensity dependences on the magnetic field strength and on the hfs splittings agreed with the first-order perturbation theory, which considers the mixing between the closely lying hfs levels in the ground state.

Measurement of the Hyperfine Structure and Zeeman Shift in Y I by High-Resolution Diode-Laser Spectroscopy

High-resolution laser spectroscopy has been performed using a tunable diode laser to measure the hyperfine structure (hfs) and Zeeman shift of two transitions in Y I. The hfs constants A of 89Y were determined for the 4d5s22D3/2 and 2D5/2 levels, and 4d5s5p4F3/2 and 4F5/2 levels; the A values of the 4F3/2 and 4F5/2 were determined for the first time. Using circular polarizations, the Zeeman spectra were selectively measured and the g factors were determined for the 4d5s5p4F3/2 and 4F5/2 levels.

Tutorial at a Japanese University as an Interactive Physics Class

Traditional lectures have been proved to have little effect in establishing physics concepts [1] and introducing interactive engagement into a physics class has been suggested by Physics Education Research (PER) groups in the Unites States in these decades [2]. Among them, Tutorial which replaces a traditional recitation is known to be especially effective although it requires substantial investment of time.

Resonance Ionization Diode-Laser Spectroscopy of Neutral Atomic Beam Produced by Pulsed-Ablation Charge Exchange.

The lithium ion beam was neutralized in a newly developed charge-exchange cell. The charge exchange was performed with sodium, lithium and iron vapors. The lithium atom was photoionized in a three-step resonance-ionization scheme where the first-step excitation was performed with a cw external-cavity diode laser. The resonance ionization with a diode laser and a pulsed dye laser was as efficient as that with two high-power pulsed dye lasers.