Calculation of equilibrium deformations of nuclei with the use of single-particle infinite potentials

Calculation of equilibrium deformations of light nuclei and rare-earth nuclei is carried out by a method suggested in [1]. For light nuclei an anisotropic oscillator potential is used, while for the rare-earth domain we employ Nilsson's potential [2]. An isospin dependence of the oscillator frequencies is employed. The results agree qualitatively with calculations made according to Strutinsky's method [3].Translated from Izvestiya VUZ. Fizika, No. 6, pp. 43–47, June, 1973.     

The Use of Multi-Pass Time-of-Flight Mass Analyzers for Nuclear-Decay Spectroscopy of Mass Identified Nuclei

The masses of ions of some keV can be determined in multi-pass time-of-flight mass analyzers [1,2] with high precision. The mass accuracies thus achieved are sufficient to determine the proton and neutron numbers for most short-lived and stable nuclei [3,5]. Recording α- or γ-radiation of the investigated nuclei in delayed coincidence to the ion arrival, one thus can perform nuclear spectroscopy of selected nuclei. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nuclear structure near the drip line studied by RNB

The use of radioactive nuclear beams (RNB) has provided an opportunity to study nuclei far from the stability line. Reaction studies using intermediate and high-energy (30–1000 AMeV) radioactive beams have revealed new structures of nuclei that are not seen in nuclei near to the stability line [1]. One such new structure is the neutron halo, a long low-density tail of the neutron distribution [2]. It has been observed in neutron drip-line nuclei, such as⁶He,¹¹Li and¹¹Be. The neutron halo has put light on many new structure problems. Among those, recent studies of a softE1 mode, a low-frequency oscillation of halo neutrons against the core, are discussed in the following section in connection with a recent (p, p′) reaction measurement [3]. Also, the effect of changes in single-particle orbitals on halo formation is discussed [4]. Another new finding is the formation of neutron skins in neutron-rich unstable nuclei [5]. The relation between the equation-of-state (EOS) of asymmetric nuclear matter and the neutron-skin thickness as well as the density distribution of nuclei far from the stability line is discussed in the last section.     

Perspectives from above and beyond the proton drip-line

This paper will review the dramatic increase in our knowledge of one and two proton unbound nuclei [1] such as recoil decay tagging [2] are revealing unique insights into the structure of nuclei beyond the proton drip-line. These studies of excited states provide complementary information to proton radioactivity studies, particularly regarding the role of deformation [3]. Radioactive beams are being used to study two-proton unbound resonances and to study explosive nuclear astrophysical reactions in the region of the proton drip-line.     

Deformation and shape coexistence in medium mass nuclei

Emerging evidence for deformed structures in medium mass nuclei is reviewed. Included in this review are both nuclei that are ground state symmetric rotors and vibrational nuclei where there are deformed structures at excited energies (shape coexistence). For the first time. Nilsson configurations in odd-odd nuclei within the region of deformation are identified. Shape coexistence in nuclei that abut the medium mass region of deformation is also examined. Recent establishment of a four-particle, four-hole intruder band in the doublesubshell closure nucleus⁹⁶Zr₅₆ is presented and its relation to the Nuclear Vibron Model is discussed. Special attention is given to the N=59 nuclei where new data have led to the reanalysis of⁹⁷Sr and⁹⁹Zr and the presence of the [404 9/2] hole intruder state as isomers in these nuclei. The low energy levels of the N=59 nuclei from Z=38 to 50 are compared with recent quadrupole-phonon model calculations that can describe their transition from near-rotational to single closed shell nuclei. The odd-odd N=59 nuclei are discussed in the context of coexisting shape isomers based on the (p[303 5/2]n[404 9/2])2^– configuration. Ongoing in-beam (t.p conversion-electron) multiparameter measurements that have led to the determination of monopole matrix elements for even-even₄₂Mo nuclei are presented, and these are compared with initial estimates using lBA-2 calculations that allow mixing of normal and cross subshell excitations. Lastly, evidence for the neutron-proton³S₁ force's influence on the level structure of these nuclei is discussed within the context of recent quadrupole-phonon model calculations.Work supported by USDOE contract Nr.W-7405-Eng-48 and NATO Grant Nr.RGO565/82.     

Scattering of ultrarelativistic deuterons by nuclei

Theoretical study of the interaction of ultrarelativistic hadrons with one another and with nuclei is stimulated by a number of experiments on the scattering of these particles with energies of ten billion electronvolt and more. It is difficult to explain the data obtained in such experiments because of the absence of a consistent relativistic quantum theory of hadrons. However, the existing experiments on the interaction of hadrons with hadrons and nuclei at high and superhigh energies can be well described phenomenologically in the framework of the diffraction approximation [1, 2], which was also used successfully earlier but at much lower, nonrelativistic energies [3, 4]. In the present paper, we derive a general formula for Hyugens's principle for monochromatic vector waves describing particles with spin 1 (for example, deuterons); this is used to obtain formulas for the cross sections of elastic and inelastic (accompanied by the emission of photons without disintegration of the particles) scattering of ultrarelativistic deuterons by nuclei with allowance for the spin and structure of the deuteron and the target nucleus; some special cases are also considered. The internal structure of the colliding nuclei, and also the possibility of excitation and disintegration of the target nuclei are taken into account by means of a generalization of the diffraction method to the case of the collision of any two nuclei, consideration being given to the interaction between each nucleon of the incident nucleus and all the nucleons of the target nucleus. In particular, this generalizes the results of [3–6] (in which diffraction scattering of elementary charged particles with spins 0, 1/2, and 1 with emission of photons was studied) to the case of composite incident particles with spin.Translated from Izvestiya Vysshikh Uchbenykh Zavedenii, Fizika, No. 9, pp. 3–8, September, 1980.     

Secondary nuclear fragment beams for investigations of relativistic fragmentation of light radioactive nuclei using nuclear photoemulsion at Nuclotron

Slowly extracted relativistic beams of light nuclei and a beam transportation line net system constitute a good base for secondary nuclear beams forming at the LHE accelerator facility. A recent years activity in the field at the Laboratory is connected with a project on study light nuclei structure by means the emulsion technique [1,2]. The paper shortly summarizes results of the work.     

Klassische Berechnung der magnetischen Suszeptibilität und der magnetischen Abschirmung der Kerne diamagnetischer Moleküle

Calculation of Magnetic Susceptibility and Magnetic Shieldin g of the Nuclei of Diamagnetic Molecules In the present work we show that the general equations for a calculation of magnetic susceptibility and magnetic shielding of the nuclei of a diamagnetic molecule based on the work of REBANE [2] are identical with the formulae derived from the classical equations of motion of the electron density of the molecule [3]. Further more it is proved that the method does not depend on the choice of coordinate origin. Conditions for an incrementary calculation of magnetic susceptibility and shielding of nuclei are formulated and applied to results given in paper [1].     

Double-quantum solid-state NMR of 13C spin pairs coupled to 14N

We examine the double-quantum magic angle spinning NMR spectra of pairs of 13C nuclei coupled to one or more 14N nuclei. The experimental spectra of 13C(2)-glycine and glycyl-[13C(2)]-glycyl-glycine are used to demonstrate the sensitivity of the spectra to the orientation of 14N quadrupole interaction tensors and to the molecular torsional angles.     

Rotational damping in ytterbium nuclei

We have made the first clear measurements of rotational damping widths in nuclei. In a mixture of three Yb nuclei, these widths are 300 +/- 60 keV between 1.2 and 1.5 MeV gamma-ray energy [approximately (37-57)Planck's constant]. Compound damping and motional narrowing are discussed in connection with these results.     

Erweiterte Gravitationstheorie und Periheldrehung

Zeitschrift für Physik A Hadrons and nuclei - In dem Beitrag ?Zur Planetenbewegung bei veränderlicher Gravitationszahl“ [9] wurde die vonHeckmann [4] gefundene strenge...     

Detecting galactic cosmic ray transuranium nuclei in olivine crystals from meteorites

Results from the experimental search for and identification of tracks from the superheavy and transuranium nuclei of galactic cosmic rays in pallacite olivine crystals, conducted as part of project OLIMPIA [1], are presented. To date, 170 crystals from Marjalahti and Eagle Station pallacites have been processed and 6800 tracks corresponding to nuclei with charges Z > 55 have been found; 45 of these are from nuclei with charges of 88 < Z < 92 and three super-long ones were produced by nuclei with Z > 105. The charge of one of these nuclei is estimated in the first approximation as Z = 119(+10,?6). Our data confirm the hypothesis of islands of stability for natural trans-Fermi nuclei.     

溴代1-己基-3-甲基咪唑离子液体与丙酮的相互作用

运用核磁共振氢谱和碳谱手段,研究了室温离了液体溴代1-己基-3-甲基咪唑([C6mim]Br)在不同浓度的离子液体/丙酮混合体系中的1H和13C化学位移．实验结果表明,离了液体[C6mim]Br的阴离子与丙酮甲基上的氢原子相互作用并形成了氢键．量子化学计算结果与核磁共振实验结果一致．     

稀土区奇质子Lu和Ta核旋称反转研究

研究了奇质子核Lu和Ta同位素链h11/2质子9／2[514]转动带旋称劈裂的系统规律，并与同一核区奇奇核的πh11/2×vi13/2两准粒子转动带低自旋区旋称劈裂规律进行了比较，指出奇质子Lu和Ta核三准粒子带的旋称反转很可能是来源于h11/2准质子和 i13/2准中子之间的相互作用。The systematic features of signature splitting of the h11/2 9/2 [ 514] rotational band in Lutetium and Tantalum isotope chains have been investigated and compared with that of πh11/2×vi13/2 2-quasiparticle band in oddodd nuclei of the same nuclear region. It is shown that signature inversion of 3-quasiparticle band of some odd- Z Lutetium and Tantalum nuclei most probably caused by the p-n interaction of h11/2 quasiproton and i13/2 quasineutron.     

Restoration of Wigner’s Sypersymmetry in Heavy and Superheavy Nuclei

Physics of Atomic Nuclei - Various aspects of restoration of Wigner’s supersymmetry [SU(4) symmetry] in heavy and superheavy nuclei are analyzed by comparing the results of calculations with...     

Quadrupole relaxation enhancement--application to molecular crystals

A general theory of field dependent spin-lattice relaxation for nuclei of the spin quantum number 1/2 (1H, 19F, 13C) caused by dipole-dipole interactions with neighboring quadrupolar nuclei (nuclei possessing a quadrupolar moment) is presented. The theory is valid for arbitrary motional conditions and should be treated as a quadrupolar counterpart of the paramagnetic relaxation enhancement theory. When the energy level splitting of the dipolar spin (I=1/2) matches one of the transition frequencies of the quadrupolar nuclei one can observe a local enhancement of the dipolar spin relaxation (referred to as "quadrupolar peaks"). To see such effects the dynamics modulating the spin interactions has to be relatively slow. This brings the system beyond the validity range of perturbation approaches and requires the stochastic Liouville equation to be applied. The presented theory describes the quadrupolar relaxation enhancement (QRE) for an arbitrary spin quantum number of the quadrupolar nuclei and includes the asymmetry of the quadrupolar coupling. It has been applied to interpret the shape of magnetization curves (amplitude of 1H magnetization versus magnetic field) for the molecular crystal [C3N2H5]6[Bi4Br18] ([C3N2H5]-imidazolium). The magnetization curves show several dips (local minima) attributed to 1H-14N quadrupolar relaxation enhancement effects. In addition, as a limiting case a perturbation approach to QRE has been presented and its validity conditions have been discussed.     

New on-line NMR/ON nuclear magnetic dipole moments near 132Sn: I. At the shell closure: meson exchange current effects

Recent on-line nuclear orientation measurements of nuclear magnetic dipole moments by the method of NMR on oriented nuclei (NMR/ON) have yielded significant new odd-A moments. These include those closest to double magic ¹³²Sn, namely, ¹³³Sb [¹³²Sn plus one g_7/2+ proton] and ¹³³Te^m [¹³²Sn with a pair of g_7/2+ protons and one hole in the h_11/2- neutron sub-shell]. These close-to-double-magic results allow stringent tests of nuclear moment theory including, as main contributions to deviations from the simple free nucleon (Schmidt limit) values, configuration mixing in the nuclear wavefunction and mesonic exchange current modification to the dipole moment operator. Comparison with theoretical prediction, using established approaches to both these corrections, is discussed showing success in medium mass nuclei comparable to results previously established in light [to ⁴⁰Ca] and heavy [near ²⁰⁸Pb] nuclei. This revised version was published online in August 2006 with corrections to the Cover Date.     

EPR of radiation defects in LiBaF 3 crystals

EPR spectra of LiBaF 3 crystals have been investigated after X-irradiation at RT. A spectrum consisting of approximately 35 nearly equidistant EPR lines has a strong angular dependence on the line intensities. The spectrum is caused by a hyperfine interaction (hfs) of a spin S =1/2 with neighbouring groups of nuclei. The observed large number of hfs lines required Li nuclei being in the first shell and fluorine nuclei in the more distant second shell. We analysed the spectrum in the F -centre model, taking reduced hfs values of the F -centre in LiF and found qualitative explanation of the number of hfs lines. The angular dependence of the line intensities could be explained by an anisotropy of the g -tensor with its main axis along the [1 v 0 v 0] axis of the crystal.