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We report on the operation of co-located 129 Xe and 131 Xe nuclear spin masers with an external feedback scheme, and discuss the use of 131 Xe as a comagnetometer in measurements of the 129 Xe spin precession frequency. By applying a correction based on the observed change in the 131 Xe frequency, the frequency instability due to magnetic field and cell temperature drifts are eliminated by two orders of magnitude. The frequency precision of 6.2 µHz is obtained for a 10 4 s averaging time, suggesting the possibility of future improvement to ≈ 1 nHz by improving the signal-to-noise ratio of the observation.

Reaction between nitrogen gas and silicon species during pulsed laser ablation

No abstract

The longitudinal electronic spin relaxation time of Cs atoms optically polarized in superfluid helium (He II, 1.5 K) has been measured with special care to cope with a serious decrease in the number of Cs atoms in the observation region. This decrease, mainly caused by helium convection in introducing the atoms into He II by laser sputtering, was significantly reduced using a new atom implantation method. Combined with a careful correction for the number of atoms, we have determined the relaxation time to be 2.24(19) s or longer, roughly twice as long as that in solid He.

We demonstrate the simultaneous production of spin-polarized ions/electrons using two-color, two-photon ionization of laser-ablated metallic atoms. Specifically, we have applied the developed technique to laser-ablated Sr atoms, and found that the electron-spin polarization of Sr+ ions, and accordingly, the spin polarization of photoelectrons is 64%±9%, which is in good agreement with the theoretical prediction we have recently reported [T. Nakajima and N. Yonekura, J. Chem. Phys. 117, 2112 (2002)]. Our experimental results open up a simple way toward the construction of a spin-polarized dual ion/electron source.

Producing Ca+ and Sr+ ions by laser ablation of pure metal samples and detecting their laser induced fluorescences, cross sections of collision induced transitions between fine-structure levels in the 4p 2PJ state of Ca+ and the 5p 2PJ state of Sr+ due to collisions with He atoms at room temperature (298 K) have been measured. The cross sections determined are σ(Ca+: 4p 2P3/2→4p 2P1/2)= 1.17±0.05 Å2, σ(Ca+: 4p 2P1/2→4p 2P 3/2) = (7.92±0.44)×10-1 Å2 and σ(Sr+: 5p 2P3/2→5p 2P 1/2) = (1.44±0.10)×10-2 Å2.

The 14 μm bands of BF3-CO complexes: Isotopedependent chaotic fine structure J. Chem. Phys. 98, 3612 (1993); 10.1063/1.464038 Freejet infrared absorption spectroscopy of rare gas-1 1BF3 complexes in the 7 μm region High resolution infrared absorption spectra of rare gas (Rg)-BF3 van del' Waals complexes are studied in the 14 f.1m region near the 1'2 band of BF3 monomer. Spectroscopic constants are determined for the 2oNe_llBF 3' Ar_JO,IlBFJ' 82-84.86Kr_IIBF3' and 84Kr-1oBF3 complexes. The observed redshifts from the monomer band origin correlate linearly with the rare gas polarizabilities. These shifts are about three times as large as those measured previously near the monomer v.) band. This mode dependence of the shifts cannot be reproduced in a consistent manner with the instantaneous vibrational dipole-induced dipole interaction model, and indicates much greater enhancement of bonding energy by the excitation of "'2 vibration. The band shifts are discussed on the basis of electrostatic interaction behveen rare gas atom and point charges on BF 3 . The anomalous band shifts for the V2 band are successfully accounted for by the interaction of vibrational dipole moment with the static induced dipole moment on the rare gas atom, which is parallel to the direction of vibrational motion. The isotope shifts observed for the Kr-BF 3 complexes and the band shifts due to the modification of force field by vdW bonding are discussed with a linear triatomic molecular model.