We have investigated the efficiency of ion trapping in a linear Paul trap. First, we measured the dependence of trapping efficiency on dc and rf voltages using a channel electron multiplier for the direct detection of the electric current of the trapped ions. The most efficient dc and rf voltages were 5.0 and 175 V, respectively. Second, we calculated the trapping efficiency using a simulation code and compared it with the experimental results. We determined that the efficiency of ion trapping decreased monotonically with increasing dc voltage and had an optimum rf voltage. From the numerical calculation, the dependences of trapping efficiency on dc and rf voltages and the initial kinetic energy of ions was derived and the optimum dc and rf voltages and the initial kinetic energy of ions were found to be 0, 210 V, and 1 eV, respectively.

Potential energy curves (PECs) for the ground and low-lying excited states of the cesium iodide (CsI) molecule have been calculated using the internally contracted multireference configuration interaction calculation with single and double excitation method with the relativistic pseudopotentials. PECs for seven Lambda-S states, X 1Sigma+, 2 1Sigma+, 3Sigma+, 1Pi, and 3Pi are first calculated and then those for 13 Omega states are obtained by diagonalizing the matrix of the electronic Hamiltonian H(el) plus the effective one-electron spin-orbit (SO) Hamiltonian H(SO). Spectroscopic constants for the calculated ground X 0+-state PEC with the Davidson correction are found to agree well with the experiment. Transition dipole moments (TDMs) between X 0 and the other Omega states are also obtained and the TDM between X 0+ and A 0+ is predicted to be the largest and that between X 0+ and B 0+ is the second largest around the equilibrium internuclear distance. The TDMs between X 0+ and the Omega=1 states are estimated to be nonzero, but they are notably small as compared with those between the 0+ states. Finally, vibrational levels of the X 0+ PEC for the two isotopic analogs, (133)CsI and (135)CsI, are numerically obtained to investigate the isotope effect on the vibrational-level shift. It has been found that the maximized available isotope shift is approximately 30 cm(-1) around nu=136.

We show that discrete-time quantum walks on the line, Z, behave as "the quantum tunneling." In particular, quantum walkers can tunnel through a double-well with the transmission probability 1 under a mild condition. This is a property of quantum walks which cannot be seen on classical random walks, and is different from both linear spreadings and localizations.

We observed the 3snp autoionizing Rydberg series of the Be atom in order to investigate the doublephotoexcitation processes in two-s-electron systems. We employed synchrotron radiation to photoexcite the Be atoms and measured the generated Be + photoions by the time-of-flight method. The 3snp ͑n =3-9͒ photoexcitation resonance peaks with interloper state of 3p4s that converges to Be + ͑3p͒ threshold were observed. We derived the resonance parameters of 3snp series from a fitting procedure and obtained the Fano parameter q, energy position E 0 , and resonance width ⌫. These parameters are in good agreement with theoretical values. In the vicinity of the 3s5p state these experimental results clearly revealed the influence of the interloper 3p4s state, and the comparison with the numerical calculations indicates that more detailed calculations might be required to fully explain this phenomenon.

We generated a 0.3-mm-diameter DC, hollow-cathode helium discharge in a gas pressure range of 10-80 kPa. In discharge plasmas, we measured position-dependent laser absorption spectra for helium 2 3 S 1 -2 3 P 0 transition with a spatial resolution of 55 µm. From the results of the analysis of the measured spectra using Voigt functions and including both the Doppler and collision broadening, we produced two-dimensional maps of the metastable 2 3 S 1 atomic densities and gas temperatures of the plasmas. We found that, at all pressures, the gas temperatures were approximately uniform in space with values in the range of 400-1500 K and the 2 3 S 1 atomic densities were >10 19 m %3 . We also found that the two-dimensional density distribution profiles became ring-shaped at high gas pressures, which is qualitatively consistent with the two-dimensional fluid simulation results.

We propose an implementation scheme for the continuous-time quantum walk using a diatomic molecule and an optical frequency comb. We show an analogy between the quantum walk and the cascade rotational transitions induced by the optical frequency comb whose frequency peaks are tuned to the pure rotational transitions in the molecule. The strategy to compensate for the centrifugal distortion of the real molecule is also demonstrated.

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We have observed K-shell and L-shell hollow beryllium atoms (2s(2)2p3s and 1s3s(2)3p) created by photoexcitation using synchrotron radiation. Resonance shapes were fitted to the Fano profile and the parameters were deduced. A Dirac-Fock calculation was performed to identify the configuration of the peaks and to predict other hollow atomic peaks. The results of the calculation were in good agreement with the experimental data. The comparison of the transition strength has revealed that the three-electron photoexcitation to the 1s3s(2)3p configuration is stronger than the two-electron photoexcitation to the 2s(2)2p3s configuration. This is attributed to the large overlap between the 2s orbital of the ground state (1s(2)2s(2)) with the orbital of the L-shell hollow state (1s3s(2)3p).