Tatsuya Minowa

Highly sensitive detection of thallium atoms using resonance ionization

Abstract Highly sensitive detection of thallium atoms has been carried out using resonance ionization. Thallium was vaporized by heating in a proportional counter cell. Two step ionization of thallium atoms was carried out with a pulsed dye laser. A sensitivity was reached in the order of one in 1013 atoms.

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.

Isotope Shifts in Gd I and Er I by UV Laser Spectroscopy

High-resolution atomic-beam laser spectroscopy in Gd I and Er I has been performed in the ultraviolet (UV) region. Isotope shifts have been measured for three UV transitions in Gd I and two transitions in Er I. Hyperfine structure constants of 155,157 Gd and 167 Er have been newly determined for two high-lying levels. Specific mass shifts and field shifts have been derived for the 4 f 7 5 d 6 s 2 –4 f 7 5 d 2 6 p and 4 f 7 5 d 6 s 2 –4 f 8 5 d 6 s transitions in Gd I as well as the 4 f 12 6 s 2 –4 f 11 5 d 6 s 2 and 4 f 12 6 s 2 –4 f 11 5 d 2 6 s transitions in Er I. Results show that the specific mass shift 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.

Measurement of Stark Shift of Potassium D Lines

High-resolution atomic-beam laser spectroscopy has been performed to study the Stark effect of K atoms. A compact electrode apparatus has been developed to produce a stable and strong electric field. The Stark shifts of the D 1 and D 2 lines as well as the splitting of the D 2 line have been measured and found to be proportional to the square of the electric field. The scalar polarizability of the D 1 line and the scalar and tensor polarizabilities of the D 2 line have been determined to be α s (4 p 2 P 1/2 ) -α s (4 s 2 S 1/2 )=81.3±2.4 kHz/(kV/cm) 2 , α s (4 p 2 P 3/2 ) -α s (4 s 2 S 1/2 )=93.0±2.5 kHz/(kV/cm) 2 , and α t (4 p 2 P 3/2 )=-27.6±0.7 kHz/(kV/cm) 2 , respectively, providing a crosscheck of the previously reported values.

Stark Effect of the Rubidium D2 Line Studied by High-Resolution Laser Spectroscopy

The Stark effect of the 5 s 2 S 1/2 –5 p 2 P 3/2 transition ( D 2 line) of Rb has been studied by high-resolution atomic-beam laser spectroscopy. The splittings of magnetic sublevels of 5 p 2 P 3/2 have been resolved, and the Stark shifts and splittings of the D 2 line have been measured at various electric fields. The scalar polarizability of the D 2 line and the tensor polarizability of the 5 p 2 P 3/2 level have been determined to be α s (5 p 2 P 3/2 ) - α s (5 s 2 S 1/2 ) = 136.95(89) kHz/(kV/cm) 2 and α t (5 p 2 P 3/2 ) = -40.91(38) kHz/(kV/cm) 2 , respectively, by considering the mixing between hyperfine structure levels of 5 p 2 P 3/2 . The precision of α t (5 p 2 P 3/2 ) has been improved by a factor of 2 compared with the previously reported values.

A Novel Method of Stabilizing Frequency-Modulated Microwave for Coherent Transient Spectroscopy

A method of stabilizing the microwave frequency modulated for the observation of transient molecular responses has been developed. Good long-term stability of the mean values of the modulated microwave frequencies is achieved; the stability is 3×10-9/day for an NEC 10V13 klystron and 10-8/day for OKI 24V11, 25V12, and 47V12 klystrons. This stabilizer has operated successfully in measuring the relaxation rate constants of weak rotational transitions of OCS and HCOOH, whose absorption coefficients are in the region 10-6-10-7 cm-1.

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.