Nuclear Spin Alignment and Alignment Correlation Terms in Mass A = 8 System

The pure nuclear spin alignments of ⁸Li and ⁸B were produced from the nuclear spin polarization applying the β-NMR method. The alignment correlation terms in the β-ray angular distribution were observed to test the G parity conservation in the nuclear β decay.     

Quadrupole Moments of Na Isotopes

The electric quadrupole coupling constants eqQ/h of ²⁰Na (I ^π = 2⁺, T _1/2 = 449.7 ms), ²¹Na (I ^π = 3/2, T _1/2 = 22.49 s) and ²⁵Na (I ^π = 5/2, T _1/2 = 59.6 s) in single crystal ZnO and TiO₂ were precisely measured by applying the β-NMR technique. The ratio of the quadrupole moments between ²⁰Na (²⁵Na) and ²¹Na was determined to be 0.728 ± 0.023 (0.011 ± 0.002).     

Temperature dependence of Knight shifts for 12 B in Pt

The Knight shift of a short lived β-emitting nucleus ¹²B (I = 1, T _1/2 = 20 ms) implanted into Pt has been measured as a function of temperature (140?600 K) by means of the β-NMR method. The relation between the Knight shift and the susceptibility for Pt was deduced, which shows the similar tendency to that for the case of ¹²B in Pd.     

Hyperfine interactions of the short-lived beta-emitter8Li in ferromagnetic Ni

To complete the systematic study on hyperfine interactions of light impurities in ferromagnetic Ni, the short-lived beta-emitter⁸Li was implanted in a thin polycrystal Ni foil. One of the final sites of⁸Li in Ni was found by means of the beta-NMR technique andits hyperfine field was determined to be -3.65(3) kOe. Simultaneously, the spin lattice relaxation time of⁸Li at the site in Ni was found to be 1.6(4) s. Based on the comparison between these values and theoretical predictions recently made by a first principle calculation, the probable site of⁸Li in Ni is implied to be an octahedral interstitial site.     

Spin-polarization of radioactive 123Ing.s. by the tilted-foil method

A spin-polarized radioactive ¹²³In (I ^π , g = 1.220(2) , T _1/2 = 5.97(5) s) beam has been successfully generated by the tilted-foil method. This nuclide is the heaviest ever polarized in its ground state by this method. Using the ISOL-based re-acceleration-type facility TRIAC, an ¹²³In_g.s. beam of 305 keV/nucleon went through a stack of 15 carbon foils with a tilt angle of 70^° , and an asymmetry of 0.76 ± 0.25% of β-decays was observed by the β-NMR technique. The asymmetry shows that the tilted-foil method combined with a re-acceleration facility is useful for producing spin-polarized beams for applications such as nuclear physics and materials science.     

Nuclear structure of proton-rich unstable nucleus 28P studied by g-factor measurement*

Nuclear structure of proton-rich unstable nucleus 28P has been studied by measuring its g-factor for the first time. The g-factor of 28P (Iπ =3+, T1/2=270.3 ms) was measured by means of β-NMR technique combined with the new polarization technique for charge exchange reaction product in the intermediate energy heavy ion collisions. The obtained g-factor of g=0.1028(27) is very much quenched from the Schmidt value,but is well reproduced by the shell model (+0.102). In connection with the magnetic moment of the mirror partner and the β-ray transition probability, the orbital angular momenta and intrinsic spins of protons and neutrons have been determined as 〈lp〉 = 0.43(29), 〈ln〉 = 1.85(29), 〈Sp〉 = 0.28(4), and 〈Sn〉 = 0.44(4).     

An enantiomeric nanoscale architecture obtained from a pseudoenantiomeric aggregate: covalent fixation of helical chirality formed in self-assembled discotic triazine triamides by chiral amplification

Covalent fixation of a chiral helical structure which is created in a self-assembling system by a chiral-amplification method based on the sergeants/soldiers principle is reported. Disk-shaped triazine triamides self-assembled to form columnar-type helical aggregates through pi-stacking interactions among the central triphenyltriazine moieties, hydrogen-bonding interactions among the amide groups, and van der Waals interactions among the alkyl groups in nonpolar solvents such as hexane, octane, toluene, and p-xylene. When the achiral triazine triamide soldier component is mixed with a tiny amount of the chiral triazine triamide sergeant component, control of the intrinsic supramolecular helicity of the self-assembled soldier component by the sergeant component leads to chiral amplification and formation of a pseudoenantiomeric aggregate with only one handedness of the helix. The helicity can be preserved by ring-closing olefin metathesis polymerization mediated by Grubbs catalyst when an achiral component with terminal olefinic groups forms the pseudoenantiomeric aggregate in the presence of a tiny amount of the chiral component without olefinic groups. After polymerization and removal of the chiral component, the polymeric architecture obtained from the achiral soldier component is optically active and thus can be regarded as an enantiomeric object in which the chiral information transferred from the chiral sergeant component is preserved. The nanoscale chiral structure is fixed perfectly, as indicated by CD spectroscopic evidence obtained in a polar THF medium at high temperature and low concentration. AFM and TEM observations show a nanoscale fibrous structure with a diameter of 2-4 nm, which corresponds to the molecular size of the triazine triamide monomer.     

Phase-dependent excitation and ionization in the multiphoton ionization regime

We theoretically study the dependence of atomic excitation and ionization on the carrier envelope phase of few-cycle laser pulses in the multiphoton ionization regime. Our theoretical results for the hydrogen atom based on the solution of the 3D time-dependent Schr?dinger equation show that the strong phase dependence can be seen in not only total ionization, but also bound-state population under the weak laser intensity regime.