Imaging of the H NMR Second Moment with C Chemical-Shift Resolution

A method of ¹³C chemical-shift-resolved ¹H second moment imaging is proposed for molecular mobility imaging of heterogeneous materials. For evaluating the ¹H second moment, the method relies on the curve fitting procedure using spin-echo shapes indirectly: The information of ¹H echo shapes is transferred to the ¹³C signal amplitude through ¹H–¹³C cross polarization and then the curve fitting is made using the ¹³C signal amplitude. The ¹³C signal is detected under ¹H dipolar decoupling and magic angle spinning, resulting in the incorporation of ¹³C chemical-shift resolution. Imaging information is included in the ¹³C signal by application of phase-encoding gradients. The second moment images obtained can reflect the molecular mobility at every molecular site separated by ¹³C chemical shifts, yielding detailed information on the molecular mobility. The method is demonstrated by spatially 1D experiments performed on a model sample.     

Time-dependent self-consistent perturbation theory and applications to molecules

The two most intense bands of the 370 nm electronic band system of tropolone have been rotationally analysed. They are separated by 18·93 cm^-1 and it has been shown that the high wavenumber band is the 0^--0^- (H₁ ¹) transition in what is almost certainly the internal hydrogen-bonding vibration v _H : the low wavenumber band is the 0⁺-0⁺ (0₀ ⁰) transition. A rotational contour analysis of both bands shows that there is an intensity alternation in K _a″ such that the ratio K _a″ even : odd is 10 : 6 in the 0⁺-0⁺ band and 6 : 10 in the 0^--0^- band. The intensity alternation, the nearly equal intensities of the 0⁺-0⁺ and 0^--0^- bands, the separation of these two bands and the anharmonic behaviour of v _H show that the separation of the 0⁺ and 0^- levels is small in the ground electronic state (probably less than 50 cm^-1) and is 18·93 cm^-1 larger in the excited electronic state.

The 0⁺-0⁺ and 0^--0^- bands are both type B showing that the electronic transition is à ¹ B ₂-X ¹ A ₁ and therefore π*-π rather than π*-n. The π*-n transition is probably shifted to high wavenumber by the internal hydrogen-bonding.     

Simultaneous GCSM description of the M1 state and the major collective bands

The generalized coherent state model is used to simultaneously describe the magnetic state 1⁺ and the collective bands: ground, beta and gamma. Effective operators for the M1 and the E2 transitions are derived. Also the M1 form factor for the (e, e′) scattering is treated in the plane wave Born approximation. The symmetry of the lowest gamma band is discussed. The application is made for ¹⁵⁴Gd, ¹⁵⁴Sm, ¹⁶⁴Dy, ¹⁶⁸Er, ¹⁷⁴Yb, ²³²Th, ²³⁸U. The agreement with the experiment is very good for both the 1⁺ state and the considered collective bands.     

Electronic structure and fluorescence spectrum of the HeO+ cation

Quantum-mechanical calculations of the potential curves of the HeO⁺ ion are preformed which correlate with four lower dissociation limits and indicate the excimer type of the ion. The transition dipole moments of the 2²Σ^?→1²Σ^? and 2⁴Σ^?→1⁴Σ ^? transitions are calculated. The energies and radiative lifetimes of vibrational levels are determined and structural and spectroscopic constants of the states 1²Σ^?, 2²Σ^?, 1⁴Σ^?, and 2⁴Σ^? are calculated. The fluorescence spectrum corresponding to the 2²Σ^?→1²Σ^? and 2⁴Σ^?→1⁴Σ ^? transitions is also calculated. The possibility of lasing at these transitions is discussed.     

Theoretical studies on geometrical and electronic structure of electroplex at the NPB/PBD interface in organic light-emitting diodes

The studies on geometrical and electronic structure of electroplex (NPB⁺PBD⁻), which is formed by NPB⁺ and PBD⁻, were carried out by simulation calculation. The calculation results indicate that the (NPB⁺PBD⁻) is formed efficiently when the positions of PBD⁻ and NPB⁺ are appropriate. The (NPB⁺PBD⁻) is energetically favored compared to isolated ions NPB⁺ and PBD⁻. So the ionic state NPB⁺ and PBD⁻ at the interface NPB/PBD inside organic light-emitting diode (OLED) tend to form electroplex. The analysis of geometrical structure data of the (NPB⁺PBD⁻) suggests that the electron transfer occurs from the PBD⁻ side to the NPB⁺ side. The lowest unoccupied molecular orbital (LUMO) of (NPB⁺PBD⁻) is localized on the PBD⁻ side and the highest occupied molecular orbital (HOMO) of (NPB⁺PBD⁻) on the NPB⁺ side. The energy gap of the (NPB⁺PBD⁻) is 1.61 eV, which approximately equals to the energy difference of 1.63 eV between the LUMO of PBD and the HOMO of NPB. The emission of electroplex is theoretically intermolecular optical transition from the LUMO of PBD to the HOMO of NPB. Because of little overlap probability between LUMOs of PBD and NPB at the NPB/PBD interface inside OLED, the exciplex of PBD and NPB is not efficiently produced.     

Fourth-generation signatures in D0-;D̄0 mixing and rare D decays

We study the effects of a fourth generation on D⁰-D̄⁰ mixing and the rare decays D⁰→μ⁺μ⁻, D→ℓ⁺ℓ ⁻X (where X is nonstrange), D→πℓ⁺ℓ⁻ and D→ϱγ (orωγ). D⁰-D̄⁰ mixing can be as large as the experimental limit of 0.5%. The fourth generation can enhance the branching ratios for the rare decays by several orders of magnitude: it can be as large as 10⁻⁹ for the decays D⁰→μ⁺μ⁻, D→ℓ⁺ℓ⁻X and D→πℓ⁺ℓ⁻. The long-distance contribution to the radiative decays is estimated to be ∼ 10⁻⁸ and is shown to be dominant in the three-generation model. The fourth generation can bring this branching ratio up to ∼ 10⁻⁶.     

Systematic study of rotational energy formulae for superdeformed bands in La and Ce isotopes

The experimental rotational spectra of superdeformed(SD) bands of ~(130)La, ~(131)Ce(1,2), ~(132)Ce(1,2,3) and133 Ce(1,2,3) in the A～130 mass region are systematically analyzed with the four parameter formula, power index formula, nuclear softness formula, and VMI model. It is observed that out of all the formulae, the four parameter formula suits best for the study of the ~(130)La, ~(131)Ce(1,2), ~(132)Ce(2,3) and ~(133)Ce(1,2,3) SD bands. The four parameter formula works efficiently in determining the band head spin of the ~(130)La, ~(131)Ce(1,2) ~(132)Ce(2,3) and ~(133)Ce(1,2,3) SD bands. Good agreement is seen between the calculated and observed transition energies whenever the accurate spin is assigned. In ~(132)Ce(1), the power index formula is found to work better than the other three formulae. The dynamic moment of inertia is also calculated for all the formulae and its variation with the rotational frequency is investigated.     

System dependence of the correlation function of IMFs in Ar + Sn at 35 MeV/u

The inclusive reduced velocity correlation functions of the intermediate mass fragments were measured in the reactions of ³⁶Ar + ^112,124Sn at 35 MeV/u. The anti-correlation is observed to be stronger in ³⁶Ar + ¹²⁴Sn system than that in ³⁶Ar + ¹¹²Sn. The difference of the correlation functions between the two reactions is mainly contributed by the particle pairs with high momenta. A three body Coulomb repulsive trajectory model is employed to calculate the emission time scale of the IMFs for the two systems. The time scale is 150 fm/c in ³⁶Ar + ¹¹²Sn and 120 fm/c in the ³⁶Ar + ¹²⁴Sn, respectively.     

电子关联与硼原子四个共壳P态的定性特征

研究了硼的²Ｐ⁰₁（基态），²Ｐ⁰₂，²Ｐ^e₁和⁴Ｐ^e₁４个Ｎ＝２共壳Ｐ态结构的定性特征，表明了电子关联对自旋极性的依赖，显示了各量子态对取向（相对于总角动量Ｌ）的偏爱，研究了它们的几何结构和内部运动模式，侧重探讨了量子力学对称性对微观系统的决定性效应。 关键词：     

Measurement of the147Gd mass excess by the (12C,9Be) reaction

The mass excess of the¹⁴⁷Gd nucleus was measured from the¹⁴⁴Sm(¹²C,⁹Be)¹⁴⁷Gd reaction using the 72 MeV¹²C beam of the Orsay MP Tandem and the “Bacchus” magnetic spectrometer. The measurement is auto-calibrated by the¹⁰Be spectrum from the¹⁴⁴Sm(¹²C,¹⁰Be) reaction. The derived value of the mass excess of¹⁴⁷Gd is ?75.401±0.025 MeV. It is compared with other recent results and with calculated values.     

The 48Ca(3He,t)48Sc reaction at 66 and 70 MeV: Reaction mechanism and Gamow-Teller strength

The ⁴⁸Ca(³He, t)⁴⁸Sc reaction has been studied at E_3He = 66 MeV and 70 MeV. Angular distributions are given from θ = 8° to 35°. The 0⁺–7⁺ multiplet in ⁴⁸Sc is strongly excited at these energies and the spectra are further characterized by some broad structures on a continuous background. Broad peaks at E_ex = 7.8, 10.6 and 13.3 MeV have an angular distribution similar to the low-lying 1⁺ state. The broad peaks are interpreted as envelopes of groups of 1⁺ states carrying a significant part of the Gamow-Teller strength. The strength distribution is consistent with a shell-model calculation. The reaction mechanism has been examined at 66 MeV. The cross section is calculated for the 0⁺–7⁺ multiplet in ⁴⁸Sc as a coherent sum of one-step and two-step processes. The two-step contribution is calculated in a full finite-range 2nd-order DWBA. The result is similar contributions from (³He, α, t) and (³He, d, t). The calculations account reasonably well for the data with the exception of the transition to 0⁺, IAS.     

Study of 122Te with charged particle reactions

The reactions ¹²²Te(d,d′)¹²²Te, ¹²³Te(d,t)¹²²Te, ¹²³Te(³He, ⁴He)¹²²Te, and ¹²¹Sb(³He,d)¹²²Te were measured with the Q3D magnetic spectrograph of the Munich Tandem Accelerator. The level scheme of ¹²²Te was extended up to about 4 MeV using also previous results and new ¹²²Te(γ,γ′)¹²²Te data. The level scheme is compared with IBA and QPM calculations. An intruder band is proposed with the 0⁺ band head at 1746 keV.     

Excited states of 176Hf

The properties of the excited levels of the even-even deformed nucleus ¹⁷⁶Hf are analyzed on the basis of available experimental data on ¹⁷⁶Ta decay. Thirty-nine new states are included in the energy-level scheme of the ¹⁷⁶Hf nucleus. The deexcitation of a number of known levels is supplemented with new transitions. New levels are included in three rotational bands, and the K _i =0 ₄ ⁺ band is identified. The 2470.95-keV level is considered as a two-phonon quadrupole-octupole state. A strong interplay of states belonging to different bands is indicated. The Coriolis interaction is calculated for pairs of K ^π = 0^? and 1^?, 0⁺ and 2⁺, and 2⁺ and 3⁺ bands. The interaction parameters are found. It is shown that the sets of positive-and negative-parity states are connected by El transitions characterized by large hindrance factors.     

Structure of low-lying <Superscript>12</Superscript>C resonances

The hyperspherical adiabatic expansion is combined with complex scaling and used to calculate low-lying nuclear resonances of ¹²C in the 3α model. We use Ali-Bodmer potentials and compare results for other potentials α-α with similar ⁸Be properties. A three-body potential is used to adjust the ¹²C resonance positions to desired values extending the applicability of the method to many-body systems decaying into three α-particles. For natural choices of three-body potentials we find 14 resonances below the proton separation threshold, i.e. two 0⁺, three 2⁺, two 4⁺, one of each of 1^±, 2^-, 3^±, 4^-, and 6⁺. The partial-wave decomposition of each resonance is calculated as a function of the hyperradius. Strong variation is found from small to large distance. The connection to previous experimental and theoretical results is discussed and agreements as well as disagreements are emphasized.     

Backward production of the B meson in K−p interactions at 4.2 GeVc

The backward production of the B(1235) meson is studied in the reaction K^?p→Σ^?π⁺ω. This reaction is observed in the final state Σ^?π⁺π⁺π^?π⁰. A π⁺ω mass enhancement is visible in the region of the B meson for events with small |u|K^? →Σ^?) squared four-momentum transfer. The properties of the enhancement agree with those of the B meson. The cross section for K^?p→Σ^?B⁺ at $\text{4.15}\text{GeV}\text{c}$ incident K^? momentum is (3.2 ± 0.5) μb. The backward production of the B meson is compared with similar baryon exchange productions of the A₁ and C(Q₁) axial vector mesons observed in the same experiment.     

Correlations in the final states ppπ+π−π+π− and ppπ+π−π+π−π+π− from 28.5 GeV/c pp collisions

We compare various invariant mass and angular distributions from the final states ppπ⁺π^?π⁺π^? and ppπ⁺π^?π⁺π^?π⁺π^? with the predictions of two models. The essential input to these models is the correct single-particle distributions with energy and momentum conservation constraints taken into account. The data is from 28.5 GeV/c pp interactions in the BNL 80-inch bubble chamber. Substantial agreement between the data and the models is obtained inferring that the kinematic constraints of energy and momentum conservation play a strong role in determining correlations between particles in these high multiplicity final states.     

15N excitation contribution to 48Ca(16O, 15N)49Sc reaction

The effect of ¹⁵N excitation process is studied in the reaction ⁴⁸Ca(¹⁶O, ¹⁵N)⁴⁹Sc. The excitation process is included into a generalized non-local optical potential for a scattersing ¹⁵N-⁴⁹Sc and is found to be responsible for a shift of a grazing peak in the exact finite-range DWBA calculation.     

Possibility of radionuclide production for PET diagnostics and brachyteraphy on the INR RAS linac

The technology of radionuclide production for positron-emission tomography on the proton linac of the Institute for Nuclear Research, Russian Academy of Sciences, is considered. A prototype of a combined target unit for production of positron-emitting radionuclides ¹¹C, ¹³N, and ¹⁸F in the proton linac beam is presented. The production of medical isotopes ¹⁰³Pd, ^{124, 125}I, and ¹³¹Cs is briefly discussed.     

HD+2，H+3和D+3与固体相互作用和三体尾流效应

从分子离子H⁺₃及其氘化同位素分子离子D⁺₃和HD⁺₂与超薄固体膜相互作用发生库仑爆炸为基础,分析讨论了H⁺₃,D⁺₃和HD⁺₂三种分子离子的形成机理,根据产物能谱分布,利用库仑爆炸技术确定了同位素分子离子HD⁺₂的结构形式,给出具体核间距数值.并确定在实验中不存在线状结构的HD⁺₂.提出一种三原子分子离子和固体相互作用中尾流效应的处理方式,通过和实验结果做比较发现这是一种非常理想的处理三体尾流效应的模式,并用之进一步确认了HD⁺₂的结构形状.文章对H⁺₃,D⁺₃和HD⁺₂三种分子离子的实验结果做了对比和讨论. 关键词： +₂')" href="#">微团簇HD⁺₂ +₃和D⁺₃')" href="#">H⁺₃和D⁺₃ 库仑爆炸 三体尾流势 团簇结构