共查询到20条相似文献,搜索用时 15 毫秒
1.
L.V. Grigorenko R.C. Johnson I.G. Mukha I.J. Thompson M.V. Zhukov 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):125-129
The theoretical approach to the two-proton radioactivity and three-body decays developed in (L.V. Grigorenko, R.C. Johnson,
I.G. Mukha, I.J. Thompson, M.V. Zhukov, Phys. Rev. Lett. 85, 22 (2000) and to be published in Phys. Rev. C) is applied to the range of light nuclear systems. We study nuclear structures,
widths, and momentum correlations for the decay fragments. Strong contradictions with experiment, as well as effects of special
interest, are found in 12O and 16Ne nuclei.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: l.grigorenko@surrey.ac.uk 相似文献
2.
F. P. Heßberger S. Hofmann D. Ackermann V. Ninov M. Leino S. Saro A. Andreyev A. Lavrentev A. G. Popeko A. V. Yeremin 《The European Physical Journal A - Hadrons and Nuclei》2000,8(4):521-535
Neutron deficient isotopes of elements Z = 86-92 have been produced by heavy-ion fusion reactions 12C + 208Pb, 209Bi, 22Ne + 208Pb, 51V + 170Er, and 50Ti + 170Er. The evaporation residues were investigated by means of α- and α-γ-spectroscopy after in-flight separation from the projectile
beam by the velocity filter SHIP and implantation into a 16-strip position-sensitive Si-detector. New or improved decay data
for 225, 226U, 216, 217m, 218Pa, 215, 216, 217Th, 214, 215, 216, 216mAc, 214Ra and 213Rn have been obtained.
Received: 5 April 2000 / Accepted: 28 July 2000 相似文献
3.
Y.H. Zhang S.Q. Zhang W.X. Huang X.H. Zhou X.C. Feng X. Xu X.G. Lei Y.X. Guo S.F. Zhu J.J. He Z. Liu S.J. Wang Y.X. Luo 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):19-22
An effort has been made to search for the decoupled bands in odd-odd 174Re via the 159Tb(20Ne,5n γ)174Re reaction through excitation functions, K x-γ and γ-γ coincidence measurements. The doubly decoupled band and the semidecoupled
one have been found in this work. Their quasiparticle configurations are proposed to be π1/2−[541] ⊗ν1/2−[521] and π1/2−[541] ⊗νi
13/2, respectively, according to the characteristics of band structures in this mass region. Another band with strongly coupled
character is also reported.
Received: 23 November 1999 / Revised version: 5 January 2000 相似文献
4.
Z.G. Gan Z. Qin H.M. Fan X.G. Lei Y.B. Xu J.J. He H.Y. Liu X.L. Wu J.S. Guo X.H. Zhou S.G. Yuan G.M. Jin 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):21-25
An isotope of the element 105 with mass number 259 has been produced via the reaction 241Am(22Ne, 4n)259Db at E
lab = 118 MeV. The reaction products were transported and collected using the helium-jet technique and the rotating wheel apparatus.
The α-decays of the products and their daughter nuclides were detected by a set of Si(Au) detectors arranged ingeniously.
The Z and A of the nuclide have been unambiguously identified by the genetic relationship between the new activity and the known nuclide
255Lr established by α-recoiled milking measurement. The new nuclide 259Db has a half-life of 0.51±0.16 s and decays by alpha-particle emission of E
α = 9.47 MeV. Furthermore, the nuclide 258Db and its daughter 254Lr have also been clearly observed using the same projectile-target combination. Their half-lives and α-particle energies
determined in this work are in agreement with previous known data, thus also proving the reliability of our assignment of
259Db.
Received: 7 December 2000 / Accepted: 6 February 2001 相似文献
5.
R.A. Radhi 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):381-385
Coulomb form factors of C4 transitions in even-even N = Z sd-shell nuclei ( 20Ne, 24Mg, 28Si and 32S) are discussed taking into account higher-energy configurations outside the sd-shell model space which are called core polarization effects. Higher configurations are taken into account through a microscopic
theory, which allows particle-hole excitations from the 1s and 1p shells core orbits and also from the 2s1d-shell orbits to the higher allowed orbits with excitations up to 4 ω. The effect of core polarization is found essential
in both the transition strengths and momentum transfer dependence of form factors, and gives a remarkably good agreement with
the measured data with no adjustable parameters. The calculations are based on the Wildenthal interaction for the sd-shell model space and on the modified surface delta interaction (MSDI) for the core polarization effects.
Received: 24 January 2002 / Accepted: 29 July 2002 / Published online: 6 March 2003
RID="a"
ID="a"e-mail: baguniv@uruklink.net
Communicated by P. Schuck 相似文献
6.
B. Saha A.K. Das P.K. Mukherjee 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):33-37
Transition energies, oscillator strengths and transition probability values for radiative transitions have been calculated
for the highly ionised atoms of Si isoelectronic sequence from Mn11+ to Kr22+ for the singly excited states up to principal quantum number n = 7. Time-dependent coupled Hartree-Fock (TDCHF) theory has been used to estimate such transition properties. Most of the
results for the oscillator strengths and transition probabilities are new. Transition energies agree reasonably well with
available spectroscopic values.
Received 25 January 2000 and Received in final form 24 October 2000 相似文献
7.
8.
A. Gillibert A. Obertelli N. Alamanos M. Alvarez F. Auger R. Dayras A. Drouart G. de France B. Jurado N. Keeley V. Lapoux W. Mittig X. Mougeot L. Nalpas A. Pakou N. Patronis E. Pollacco F. Rejmund M. Rejmund P. Roussel-Chomaz H. Savajols F. Skaza Ch. Theisen 《The European physical journal. Special topics》2007,150(1):161-163
27Ne has been investigated through the one neutron transfer reaction 26Ne(d,p)27Ne in inverse
kinematics at 9.7 MeV/nucleon. The results support the existence of a low lying negative parity state
in 27Ne which is a signature of a reduced sd-fp shell gap in the N = 16 neutron rich region, at variance
with stable nuclei. 相似文献
9.
T. Mercouris C.A. Nicolaides 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(2):241-248
By implementing a time-independent, nonperturbative many-electron, many-photon theory (MEMPT), cycle-averaged complex eigenvalues
were obtained for the He atom, whose real part gives the field-induced energy shift, Δ(ω
1, F
1;ω
2, F
2,ϕ), and the imaginary part is the multiphoton ionization rate, Γ(ω
1, F
1;ω
2, F
2,ϕ), where ω is the frequency, F is the field strength and ϕ is the phase difference. Through analysis and computation we show that, provided the intensities
are weak, the dependence of Γ(ω
1, F
1;ω
2, F
2,ϕ) on ϕ is simple. Specifically, for odd harmonics, Γ varies linearly with cos(ϕ) whilst for even harmonics it varies linearly
with cos(2ϕ). In addition, this dependence on ϕ holds for Δ(ω
1, F
1;ω
2, F
2,ϕ) as well. These relations may turn out to be applicable to other atomic systems as well, and to provide a definition of
the weak field regime in the dichromatic case. When the combination of (ω
1, F
1) and (ω
2, F
2) is such that higher powers of cos(ϕ) and cos(2ϕ) become important, these rules break down and we reach the strong field
regime. The herein reported results refer to Γ(ω
1, F
1;ω
2, F
2,ϕ) and Δ(ω
1, F
1;ω
2, F
2,ϕ) for He irradiated by a dichromatic ac-field consisting of the fundamental wavelength λ = 248 nm and its 2nd, 3rd and 4th
higher harmonics. The intensities are in the range 1.0×1012-3.5×1014 W/cm2, with the intensity of the harmonics being 1-2 orders of magnitude smaller. The calculations incorporated systematically
electronic structure and electron correlation effects in the discrete and in the continuous spectrum, for 1S, 1P, 1D, 1F, 1G, and 1H two-electron states of even and odd parity.
Received 9 July 2000 and Received in final form 2 November 2000 相似文献
10.
Z.-C. Yan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):15-18
The fully correlated calculations of the Zeeman gJ factors for the first three quartet S states of lithium are presented, including relativistic and radiative corrections of
orders α2, α2
m/M, and α3. The isotope shifts in gJ are predicted precisely for various isotopes of lithium.
Received 4 December 2000 and Received in final form 26 September 2001 相似文献
11.
E. Träbert H.-P. Garnir P.-D. Dumont T. Bastin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):25-31
Peculiar properties of ion-atom collision systems, in particular deviations from statistical populations of singlet and triplet
levels, can be studied by optical spectroscopy. We have extended earlier studies by VUV spectroscopy of a number of collision
systems at various collision energies in the 0.01-MeV/nucleon to 1-MeV/nucleon range, involving H2
+, H+, He+, He2+, Ne+, Ar+, and N2
+ as projectiles and Ne, Ar, and N2 as target gases. Statistically significant deviations of the relative intensities of singlet and triplet lines from simple
ratios are observed in the displaced terms of the valence shell of Ne III, corroborating and extending earlier work. For Ar
III, the energy dependences of singlet-to-triplet excitation ratios are very different for different projectiles. For N II,
in contrast, all observed line ratios are practically independent of the projectile energy.
Received 17 November 2000 and Received in final form 31 January 2001 相似文献
12.
R.R. Rodríguez-Guzmán J.L. Egido L.M. Robledo 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):37-47
The Angular Momentum Projected Generator Coordinate Method, with the quadrupole moment as collective coordinate and the Gogny
force (D1S) as the effective interaction, is used to describe the properties of the ground state and low-lying excited states
of the even-even neon isotopes 20-34Ne, that is, from the stability valley up to the drip line. It is found that the ground state of the N = 20 nucleus 30Ne is deformed but to a lesser extent than the N = 20 isotope of the magnesium. In the calculations, the isotope 32Ne is at the drip line in good agreement with other theoretical predictions. On the other hand, rather good agreement with
experimental data for many observables is obtained.
Received: 19 Novemeber 2002 / Accepted: 24 January 2003 / Published online: 8 April 2003 相似文献
13.
L. Zhang W. Kleemann J. Dec R. Wang M. Itoh 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(2):163-171
The dielectric permittivity ε′ - i
of SrTi 18O 3 (STO18) is studied under a dc electric field E as a function of the temperature, T. In ε′
vs.
T, a double-peak is found when 0 < E < 30 KV/m. While the peak at high-T is attributed to the smeared ferroelectric phase transition, the low-T one is induced by domain wall motion. The transverse Ising model including an external homogeneous and quenched random-fields
is successfully used to describe both the smeared phase transition and the domain wall response in the low-T domain state. The calculations are in good agreement with the experimental results.
Received 4 January 2002 / Received in final form 25 March 2002 Published online 19 July 2002 相似文献
14.
V. P. Ladygin L. S. Azhgirey S. V. Afanasiev V. V. Arkhipov V. K. Bondarev G. Filipov A. Yu. Isupov V. I. Ivanov A. A. Kartamyshev V. A. Kashirin A. N. Khrenov V. I. Kolesnikov V. A. Kuznetsov N. B. Ladygina A. G. Litvinenko S. G. Reznikov P. A. Rukoyatkin A. Yu. Semenov I. A. Semenova G. D. Stoletov V. N. Zhmyrov L. S. Zolin 《The European Physical Journal A - Hadrons and Nuclei》2000,8(3):409-416
The tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 4.5 GeV/c on beryllium at an angle of 80 mr in the vicinity of baryonic resonances excitation have been measured. The Ayy data being in good agreement with the previous results obtained at a zero angle demonstrate an approximate t scaling up to - 0.9 (GeV/c)2. The results of the experiment are compared with the predictions of the multiple-scattering and -meson exchange models.
Received: 20 April 2000 / Accepted: 29 May 2000 相似文献
15.
U.C. Bergmann M.J.G. Borge J. Cederkäll C. Forssén E. Fumero H.O.U. Fynbo H. Gausemel H. Jeppesen B. Jonson K. Markenroth T. Nilsson G. Nyman K. Riisager H. Simon O. Tengblad L. Weissman F. Wenander K. Wilhelmsen Rolander 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):279-284
The β-decays of the neutron-rich nuclei 12Be and 29Ne have been studied. The statistical correlations between the almost identical half-lives of 12Be and its daughter 12B are analysed for a large sample of 12Be decay data. Stringent mutual bounds are obtained on the parameter set, leading to a precise determination of the 12Be half-life of 21.50±0.04 ms. From a simultaneous detection of β-particles and neutrons from the decay of 29Ne the neutron emission probability, Pn, is determined to 17±5%. No indication of two-neutron emission is seen from this nucleus. An upper limit of 2.2% (90% confidence
level) is established for P2n.
Received: 3 May 2001 / Accepted: 6 August 2001 相似文献
16.
A. Latz M. Letz 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(3):323-343
The theory of light scattering for a system of linear molecules with anisotropic polarizabilities is considered. As a starting
point for our theory, we express the result of a scattering experiment in VV and VH symmetry as dynamic correlation functions
of tensorial densities ρ
lm(q) with l = 0 and l = 2. l, m denote indices of spherical harmonics. To account for all observed hydrodynamic singularities, a generalization of the theory
of Schilling and Scheidsteger [1] for these correlation functions is presented, which is capable to describe the light scattering
experiments from the liquid regime to the glassy state. As a microscopic theory it fulfills all sum rules contrary to previous
phenomenological theories. We emphasize the importance of the helicity index m for the microscopic theory by showing, that only the existence of m = 1 components lead to the well known Rytov dip in liquids and to the appearance of transversal sound waves in VH symmetry
in the deeply supercooled liquid and the glass. Exact expressions for the phenomenological frequency dependent rotation translation
coupling coefficients of previous theories are derived.
Received 3 July 2000 and Received in final form 7 November 2000 相似文献
17.
A.N. Wilson C.W. Beausang N. Amzal D.E. Appelbe S. Asztalos P.A. Butler R.M. Clark P. Fallon A.O. Macchiavelli 《The European Physical Journal A - Hadrons and Nuclei》2000,9(2):183-189
High-spin states in neutron-rich nuclei, populated following deep-inelastic multi-nucleon transfer, have been studied using
the GAMMASPHERE array at the LBNL, USA. A 64Ni beam at an energy ∼ 15% above the Coulomb barrier was incident upon a thick 208Pb target, leading to the population of more than 130 different nuclei. The strongest channels correspond to nuclei close
to the projectile and target, although transfer of up to 50 nucleons has been observed. New high-spin states in neutron-rich
60,62Fe and 68,70,72Zn nuclei have been observed. Some limitations of this method of high-spin spectroscopy are discussed, including the apparent
difficulty of populating odd-odd and odd-even isotopes via this type of reaction. The data have been searched for superdeformed
(SD) states in the A = 190-200 region, but no evidence for their presence has been found.
Received: 14 April 2000 / Accepted: 12 September 2000 相似文献
18.
A. Prévost N. Buforn A. Astier R. Duffait M. Meyer S. Perriès N. Redon O. Stézowski A. Bauchet I. Deloncle M.G. Porquet A. Görgen H. Hübel E. Mergel S. Neumann D. Roßbach N. Nenoff G. Schönwaßer A.N. Wilson R. Lucas F.A. Beck D. Curien G. Duchêne B.J.P. Gall N. Kintz J.P. Vivien D.M. Cullen 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):13-19
We report the identification of six new superdeformed (SD) bands in 197,198Pb observed with the EUROBALL IV spectrometer. The results are interpreted in the framework of cranked Hartree-Fock calculations
with approximate projection on the particle number by means of the Lipkin-Nogami method. A mixing between quasi-particle excitations
and an octupole vibration is suggested in the two SD isotopes. We have estimated the ordering of the neutron valence orbitals
and confirm indirectly a N = 118 SD gap.
Received: 20 December 2000 / Accepted: 24 January 2001 相似文献
19.
A 34Si-decay of 242Cm has been reported by Oglobin et al. But an interpretation of this 34Si emission as a ternary high-energy particle emission accompanying the fission of 242Cm can be proposed as well.
Received: 18 October 2000 / Accepted: 8 November 2000 相似文献
20.
M.V. Polyakov A. Sibirtsev K. Tsushima W. Cassing K. Goeke 《The European Physical Journal A - Hadrons and Nuclei》2000,9(1):115-118
The possibility for an observation of a narrow penta-quark Z+-baryon in NN reactions is discussed. It is shown that the pp↦nΣ+
K
+ reaction at excess energies around 100 MeV above threshold provides optimal conditions for Z+-baryon detection by an analysis of the nK+ invariant mass spectrum, if the Z+ mass is located around 1.5 GeV involving a rather narrow width.
Received: 24 May 2000 / Accepted: 3 August 2000 相似文献