Showing papers by "Takashi Kubo published in 2006"
TL;DR: An exclusive measurement has been made of the Coulomb dissociation of the two-neutron halo nucleus 11Li at 70 MeV/nucleon at RIKEN, where strong low-energy E1 excitation is observed, which represents the strongest E1 transition ever observed at such low excitation energies.
Abstract: An exclusive measurement has been made of the Coulomb dissociation of the two-neutron halo nucleus $^{11}\mathrm{Li}$ at $70\text{ }\text{ }\mathrm{MeV}/\mathrm{nucleon}$ at RIKEN. Strong low-energy (soft) $E1$ excitation is observed, peaked at about ${E}_{\mathrm{x}}=0.6\text{ }\text{ }\mathrm{MeV}$ with $B(E1)=1.42(18)\text{ }\text{ }{\mathrm{e}}^{2}\text{ }{\mathrm{fm}}^{2}$ for ${E}_{\mathrm{rel}}\ensuremath{\le}3\text{ }\text{ }\mathrm{MeV}$, which was largely missed in previous measurements. This excitation represents the strongest $E1$ transition ever observed at such low excitation energies. The spectrum is reproduced well by a three-body model with a strong two-neutron correlation, which is further supported by the $E1$ non-energy-weighted cluster sum rule.
207 citations
TL;DR: The static second hyperpolarizabilities (γ) of polycyclic hydrocarbons involving phenalenyl radical units, IDPL and PDPL, are calculated by the hybrid density functional theory (DFT), BHandHLYP, method as mentioned in this paper.
136 citations
TL;DR: This work confirms that open-shell singlet conjugated molecules with intermediate diradical characters constitute a new class of third-order nonlinear optical systems, whose gamma values can be controlled by the Diradical character in addition to the conjugation length.
Abstract: The origin of the diradical character dependence of the second hyperpolarizability (γ) of neutral singlet diradical systems is clarified based on the perturbation formula of γ using the simplest diradical molecular model with different diradical characters, i.e., H2 under bond dissociation. The enhancement of γ in the intermediate diradical character region turns out to originate from the increasing magnitude of the transition moment between the first and second excited states and the decrease of that between the ground and first excited states, respectively, with the increase in diradical character. This feature confirms that open-shell singlet conjugated molecules with intermediate diradical characters constitute a new class of third-order nonlinear optical systems, whose γ values can be controlled by the diradical character in addition to the conjugation length.
87 citations
Journal Article•
47 citations
TL;DR: In this paper, the static second hyperpolarizability of a singlet diradical system involving phenalenyl radicals linked with acetylene π-conjugated bridge was investigated.
31 citations
TL;DR: These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in (27,28)Ne nuclei caused by a vanishing N=20 shell gap at Z=10.
Abstract: This Letter reports on the (1)H((28)Ne, (28)Ne) and (1)H((28)Ne, (27)Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2(+) excited state of (28)Ne, and using the previously determined BE(2) value, the neutron quadrupole transition matrix element has been calculated to be M(n)=13.8 +/- 3.7 fm(2). In the neutron knockout reaction, two low-lying excited states were populated in (27)Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in (27,28)Ne nuclei caused by a vanishing N=20 shell gap at Z=10.
30 citations
TL;DR: In this paper, the intersite interaction effects on the average diradical character and size dependences of open-shell singlet one-dimensional systems were examined using hydrogen chain models (H 2 n ) with different chain lengths and bond-length alternations (BLA).
30 citations
TL;DR: In this article, the structural dependence of static second hyperpolarizabilities of polycyclic diphenalenyl radicals was investigated using the hybrid density functional theory method, and it was shown that the diradical character of as -IDPL (0.923) is larger than that of IDPL(0.770) and is close to 1.
17 citations
TL;DR: In this article, the authors developed an evaporator by induction heating with an induction coil covered by ceramics in vacuum and surrounding the pure Fe rod with noncontact, and the typical power and frequency of the induction currents range from 300to800W and from 30to40kHz.
Abstract: Multiply charged Fe ions are produced from solid material in a 2.45GHz electron cyclotron resonance (ECR) ion source. We develop an evaporator by induction heating with an induction coil covered by ceramics in vacuum and surrounding the pure Fe rod with noncontact. The typical power and the frequency of the induction currents range from 300to800W and from 30to40kHz, respectively. The evaporator is inserted into the ECR plasma from the mirror endplate along the geometrical axis of the mirror field. Argon gas is usually chosen for supporting gas, and the working pressure is about 10−4–10−3Pa. The multicharged Fe ions are extracted from the opposite side of mirror and against the evaporator, and then multicharged Fe ion beam is formed. We compare the production of multicharged iron ions by using this source with our previous methods.
6 citations
01 Dec 2006
TL;DR: In this article, a new concept on magnetic field of plasma production and confinement has been proposed to enhance efficiency of an electron cyclotron resonance (ECR) plasma for broad and dense ion beam source under the low pressure.
Abstract: A new concept on magnetic field of plasma production and confinement has been proposed to enhance efficiency of an electron cyclotron resonance (ECR) plasma for broad and dense ion beam source under the low pressure. The magnetic field configuration is constructed by a pair of comb‐shaped magnet which has opposite polarity each other, and which cylindrically surrounds the plasma chamber. This magnetic configuration suppresses the loss due to ExB drift, and then plasma confinement is enhanced. The resonance zones of the fundamental and the second harmonics for 2.45GHz microwaves detach from the wall of the chamber. The connection length of the magnetic field lines through the resonance zone is elongated, and the confinement is better than that of the simple multipole magnetic field. The 2.45 GHz microwaves are fed from the side wall by the rod antenna. The electron density attained to about four times cutoff density for the 2.45GHz microwave at the low Ar pressure below 0.08Pa and also the low microwave power below 300W. We compare profiles of the electron density and temperature in the comb‐shaped magnetic field configuration with those in the simple multipole magnetic field.
5 citations
TL;DR: In this article, the authors reported hydrogen absorption property of newly-synthesized RAP (rubeanic acid polymer)-protected palladium nanoparticle (RAP-Pd) from powder X-ray diffraction measurements.
Abstract: This study reports hydrogen absorption property of newly-synthesized RAP (rubeanic-acid polymer)-protected palladium nanoparticle (RAP-Pd) From powder X-ray diffraction measurements, the lattice constant of Pd nanoparticle was revealed to increase by 011 A under 600 Torr hydrogen gas condition at room temperature, indicating that the hydrogen absorption occurs in the Pd nanoparticle Solid-state 2H-NMR spectrum under deuterium gas showed that three different components exist in RAP-Pd, which are derived from imino group, terminal amino group in the RAP and absorbed deuterium atom inside the Pd nanoparticle This result gives an expectation of the hydrogen absorption in RAP itself
Abstract: The Coulomb dissociation of 27P was studied experimentally using 27P beams at 57 MeV/nucleon with a lead target. The E2 gamma decay width of the first excited state in 27P was determined to be (2.8 ± 0.5) × 10−5 eV. The total (M1+E2)gamma decay width of the state, which is of astrophysical interest, is estimated by combining the experimental result and a shell model calculation. The reaction rate of 26Si(p, γ)27P is deduced from the estimated total gamma decay width. The astrophysical implication derived from estimated gamma decay width is discussed.
27 Oct 2006
10 Oct 2006
TL;DR: In this article, angle-integrated and differential cross sections for Ex = 885 keV and 2321 keV states were obtained by measuring de-excitation γ rays and scattering angles of 32Mg.
Abstract: Proton inelastic scattering was applied to 32Mg located at the island of inversion to study higher excited states. Angle-integrated and differential cross sections for Ex = 885 keV and 2321 keV states were obtained by measuring de-excitation γ rays and scattering angles of 32Mg. From the present analysis, the transferred angular momentum from the ground state to 2321 keV state was close to ΔL = 4 rather than ΔL = 3.
TL;DR: In this paper, the Coulomb dissociation of 27P was studied experimentally using 27P beams at 57 MeV/nucleon with a lead target, and the E2 gamma decay width was determined to be (2.8 ± 0.5) × 10−5 eV. The total (M1+E2)gamma decay width of the state, which is of astrophysical interest, was estimated by combining the experimental result and a shell model calculation.
Abstract: The Coulomb dissociation of 27P was studied experimentally using 27P beams at 57 MeV/nucleon with a lead target. The E2 gamma decay width of the first excited state in 27P was determined to be (2.8 ± 0.5) × 10−5 eV. The total (M1+E2)gamma decay width of the state, which is of astrophysical interest, is estimated by combining the experimental result and a shell model calculation. The reaction rate of 26Si(p, γ)27P is deduced from the estimated total gamma decay width. The astrophysical implication derived from estimated gamma decay width is discussed.
TL;DR: The title compound, C30H18, is located on an inversion center and has an almost completely planar geometry as discussed by the authors, which is the most similar to the one of the present compound.
Abstract: The molecule of the title compound, C30H18, is located on an inversion center and has an almost completely planar geometry.