共查询到20条相似文献,搜索用时 240 毫秒
1.
D P Ahalpara 《Pramana》1979,12(2):179-201
The low-lying collective bands of positive parity states in (fp) shell nuclei are described in the deformed Hartree-Fock method by projecting states of definite angular momenta from ‘the
lowest energy intrinsic states in (sd)−1 (fp)
n+1 configurations. The modified Kuo-Brown effective interaction for (fp) shell and modified surface delta interaction (MSDI) for a hole in (sd) shell with a particle in (fp) shell have been used.
The collective bands of states are in general well reproduced by the effective interactions. The excitation energies of the
band head states are however off by about one MeV. The calculated magnetic moments of the band headj=3/2+ states are in reasonable agreement with experiment. Using effective chargese
p=1.33e ande
n=0.64e we get fairly good agreement forE(2) transitions. The hinderedM(1) transition strengths are reproduced to the correct order however they are slightly higher compared to experiment. 相似文献
2.
Chengying Xie Xiaohong Zhou Yuhu Zhang Yingxiang Guo Xiangguo Lei Yong Zheng Minliang Liu Litao Song Hualei Wang Haiping Yu Wentao Guo Peng Luo Zhijun Wu Lihua Zhu Xiaoguang Wu 《中国科学G辑(英文版)》2005,48(4):442-449
High-spin states in 190Tl have been studied via the 160Gd(35Cl, 5nγ) reaction. The level scheme, consisting of the πh
9/2⊗vi
13/2 oblate band and a cascade with character of single particle excitations, has been established. Spin values have been firmly
assigned to the oblate band in 190Tl, resulting in low-spin signature inversion in the πh
9/2⊗vi
13/2 oblate band for the first time. Based on the similarity of the level structure in doubly odd Tl nuclei, spin values for the
oblate bands in 192–200Tl should be re-assigned, and a consistent low-spin signature inversion has occurred in these oblate deformed nuclei. The
low-spin signature inversion phenomena can be interpreted qualitatively by using the 2-quasiparticle plus rotor model including
p-n residual interactions. 相似文献
3.
The Hartree-Fock (HF) minima for the nucleus28Si were obtained for the prolate, oblate and spherical shapes using the interaction obtained by Preedom and Wildenthal. The
interaction gives rise to large energy separation between the prolate and the oblate shapes. The spherical solution is just
2 MeV above the lowest HF (oblate) minimum. The spectrum projected from the oblate HF state is in good agreement with the
experimental spectrum. The transition probabilities for the different energy levels also agree reasonably well. The configuration
mixing calculations performed on the basis of states projected from the three shapes indicate that there is no significant
mixing of different projected states. The second 0
2
+
state, thus obtained, corresponds to the third 0
3
+
state in the experimental spectrum and stems dominantly from the spherical HF state. It is seen that the structure of the
energy levels of28Si, especially the second 0
2
+
level is very sensitive to the two body interaction. The results are compared with those obtained using the renormalised
interaction of Kuo. 相似文献
4.
Mikhaylova M. Jo Y. S. Kim D. K. Bobrysheva N. Andersson Y. Eriksson T. Osmolowsky M. Semenov V. Muhammed M. 《Hyperfine Interactions》2004,159(1-4):257-260
The g-factor of the exteremely proton-rich nucleus 23Al(T
1 / 2 = 0.47 s) has been measured for the first time, applying β-NMR technique on this nucleus implanted in Si. The obtained ∣g∣ = (1.58 ± 0.2) suggests that the spin of the ground state of 23Al is 5 / 2. The magnetic moment is determined as ∣μ∣ = (3.95 ± 0.55) μ
N
. 相似文献
5.
Isomeric cross-section ratios of evaporation residues formed in12C+93Nb and16O+89Y reactions were measured by recoil catcher technique followed by off-line γ-ray spectrometry in the beam energy range of
55.7–77.5 MeV for12C and 68–81 MeV for16O. The isomeric cross-section ratios were resolved into that for complete and incomplete fusion reactions. The angular momentum
of the intermediate nucleus formed in incomplete fusion was deduced from the isomeric cross-section ratio by considering the
statistical deexcitation of the incompletely fused composite nucleus. The data show that incomplete fusion is associated with
angular momenta slightly smaller than critical angular momentum for complete fusion, indicating the deeper interpenetration
of projectile and target nuclei than that in peripheral collisions. 相似文献
6.
V.V. Glagolev K.G. Gulamov V.D. Lipin S.L. Lutpullaev K. Olimov Kh.K. Olimov A.A. Yuldashev B.S. Yuldashev 《The European Physical Journal A - Hadrons and Nuclei》2001,11(3):285-296
The data on investigation of inelastic interactions of 16O nuclei in a hydrogen bubble chamber at an incident momentum of 3.25 A GeV/c are presented. Separate characteristics as fragments isotope composition and topological cross-sections of fragmentation
channels are given. The processes of formation of light fragments and unstable nuclei, and the break-up of the 16O nucleus into multicharge fragments are investigated. A comparison between the experimental data and the calculations of
the cascade fragmentation evaporation model (CFEM) is made. The observed singularities of the interactions point out the important
role of the nucleus α-cluster structure in the formation of the final products.
Received: 9 January 2001 / Accepted: 13 June 2001 相似文献
7.
Configuration assignments are derived for the observed energy levels in the odd-odd deformed nucleus170Lu99 based on the calculations of the two-particle band head energies for a zero range residual interaction, the beta-feeding
characteristics, and the observed features for similar bands in the neighbouring nuclei. In particular, specific assignments
are given for theJ
π
=1+ levels at 198.4 keV, 349.0 keV and 785.5 keV. The ambiguities with respect to the assignments for theK
π=3− bands are discussed. A new isomer withJ
π
=7+ and half-life of several seconds is predicted around (225±25) keV and experiments are suggested to identify it. 相似文献
8.
Raymond K. Sheline C. F. Liang P. Paris P. Alexa J. Kvasil 《Czechoslovak Journal of Physics》2004,54(7):721-738
Minor changes in the assignments of gamma rays following the alpha decay of228Pa in two previous studies make possible a reinterpretation of224Ac into two alternative level schemes. The resulting level structures arise from the reflection asymmetric configurations
π3/2±(0.0 −0.3)−ν3/2±(−0.1 0.6), π5/2±(0.0 −0.2)±ν3/2±(−0.1 0.6) and π5/2±(0.0 −0.2)±ν1/2±(0.2 −0.1 3) which give rise to eitherK=0± or 1±,K=4±,K=2± andK=3± parity doublet bands. The bands with appreciable band structure, namelyK=0± or 1± andK=3±, have average parity doublet splittings of 11.0 and 5.8 keV respectively. These are extremely small values and suggest that224Ac is the most octupole deformed nucleus studied thus far. A method of calculating the parity doublet splitting in odd-odd
nuclei is suggested and tested for224Ac. It seems to work remarkably well. The systematics of the hindrance factors for the bands with extended band structures
confirm their interpretations as band structures. Finally, the two alternative level schemes are analyzed in the framework
of the axially-symmetric rigid rotor model including the Coriolis interaction. 相似文献
9.
The structure of the collective bands in77Kr is investigated within our deformed shell model (DSM) based on Hartree-Fock states. The different levels are classified
into collective bands on the basis of their B(E2) values. The calculatedK = 5/2+ ground band agrees reasonably well with the experiment. An attempt has been made to study the structure of the 3-quasiparticle
band based on large J state in this nucleus. The calculated collective bands, the B(E2), and B(M1) values are compared with
available experimental data. The nature of alignments in the low-lying bands is also analyzed. 相似文献
10.
By expanding the Bargmann-Segal integral transform of nomi and overlap kernels in appropriately SU(3) coupled Bargmann space functions, the calculation of norm and overlap matrix elements in a cluster model basis is reduced to purely algebraic techniques involving the algebra of SU(3) recoupling transformations. This technique has been further developed to make calculations possible for systems of two heavy fragments other than closed-shell nuclei. In one application of the method, analytic expressions are given for the norms of binary fragment systems in which a light fragment of mass number ?, ? ? 4, is combined with a heavy fragment of mass number . The fragment nuclei with different p- and sd-shell structure illustrate somewhat different problems in the recoupling technique. In a second application, spectroscopic amplitudes are calculated for the most important open channels of the 12C+ 12C resonances. Eigenvalues and eigenvectors of the antisymmetrizer are evaluated in a “molecular basis” of the 12C + 12C system, in which each 12C nucleus is assumed to have SU(3) symmetry (04) with internal rotational excitations of 0+,2+ and 4+. Reduced width amplitudes are calculated connecting such normalized, fully antisymmetrized molecular basis states to exit channels which include: α+20Ne with 20Ne internal functions of (80) SU(3) symmetry, (K = 0+ band, and (82) SU(3) symmetry, (K = 2? band); 16O+8Be; and 23Na+p or 23Mg+n fragments with 23Na or 23Mg excitations in rotational bands of SU(3) symmetry (83). 相似文献
11.
Thermonuclear reaction rates for the temperature range 1≤T
9≤5 have been extracted from experimentally measured (p, n) cross sections for45Sc50Ti,51V,54Cr,55Mn and59Co nuclides below 5 MeV bombarding energy. These reaction rates are important in the build-up of medium and heavy nuclides
in the stellar evolution process and nucleosynthesis. To enhance the usefulness of these reaction rates in astrophysical calculations,
they have been fitted to an analytic function of temperature, valid throughout the temperature range considered here. 相似文献
12.
Spectroscopic investigations were performed on a single crystal of CaF2 doped with 0.05% Pr3+. Three different Pr3+ sites with different luminescent properties were identified. The 4f2 →4f15d1 excitation spectrum of the first site has a sharp maximum at 221.3 nm. Excitation in the 4f5d bands of this site yields strong 4f5d emissions in the UV/VIS part of the spectrum and also weaker intraconfigurational 4f2 emissions. By comparing the intraconfigurational 4f emissions and their decay times with data from the literature, these 4f5d bands are assigned to transitions on Pr3+ ions on a site with C4V symmetry. The fd excitation spectrum of the second site has a zero phonon line at 223.3 nm. Upon selective excitation in this band, only 4f5d emission is observed. Probably, these 4f5d bands correspond to Pr3+ ions on a Oh site. The third set of 4f5d bands has a 4f5d onset at 208 nm. By comparison of the luminescence spectra of the intraconfigurational 4f2 transitions with literature data, these transitions are assigned to Pr3+ on an L site. Excitation in these 4f5d band yields 1S0 emission followed by emission from the 3P0 state. The present results clarify some contradictions reported in the literature. 相似文献
13.
H. Nagahiro S. Hirenzaki E. Oset M.J. Vicente Vacas 《Physics letters. [Part B]》2005,620(3-4):125-130
We present results on the production of bound states of Θ+ in nuclei using the (K+,π+) reaction. By taking into account the states obtained within a wide range of strength of the Θ+ nucleus optical potential, plus the possibility to replace different nucleons of the nucleus, we obtain an excitation spectra with clearly differentiated peaks. The magnitude of the calculated cross sections is well within reachable range. 相似文献
14.
J. Gerl G.D. Dracoulis A.P. Byrne A.R. Poletti S.J. Poletti A.E. Stuchbery 《Nuclear Physics A》1985,443(2):348-364
High-spin states in 166W and 167W were populated by the reactions 142Nd(28Si,4n)166W, 142Nd(28Si,3n)167W and 147Sm(24Mg,4n)167W. From the γ-decay the yrast band and a side band (with assumed negative parity) were identified to high spins. There is evidence for a second side band in 167W. The observed backbend of the yrast sequences and band-crossing anomalies in the side bands are discussed in conjunction with cranked-shell-model calculations. A systematic comparison is made between the yrast bands of 166,167,168W in order to understand the structure of the second backbend in 168W. 相似文献
15.
JM Chatterjee M Saha Sarkar S Bhattacharya P Banerjee S Sarkar RP Singh S Murulithar RK Bhowmik 《Pramana》2001,57(1):165-169
High-spin states of 95,97Mo (Z=42, N=53,55) nuclei have been investigated through 82Se(18O, xn) reaction at Eb=60 MeV. The level scheme in 95Mo has been observed upto ≏ 10 MeV in the present experiment. The level structure shows mainly single particle character.
In 97Mo, the ground state level sequence has been extended to ≏ 4.5 MeV while the previous information had been up to 2.4 MeV.
A negative parity band built on 1437 keV (11/2−) excited state has been extended to 5.5 MeV. The structure seems to show a coexistence of single particle and collective
modes of excitation. Properties of both the nuclei have been compared with shell model calculations using OXBASH. 相似文献
16.
采用傅里叶变换红外光谱仪记录了富含15N216O同位素的一氧化二氮样品在1650-3450 cm-1波段的高分辨振转光谱,得到了该同位素分子超过7300吸收谱线位置的实验值,经分析实验精确度好于5.0×10-4 cm-1. 基于有效哈密顿量模型预测和带带转动分析,确定了所有吸收线的归属;获得了29个新吸收带的振转光谱参数,并优化了其他44个吸收带的光谱参数值. 并且发现有效哈 相似文献
17.
H. Watanabe K. YamaguchiA. Odahara T. SumikamaS. Nishimura K. YoshinagaZ. Li Y. MiyashitaK. Sato L. PróchniakH. Baba J.S. BerrymanN. Blasi A. Bracco F. Camera J. ChibaP. Doornenbal S. GoT. Hashimoto S. HayakawaC. Hinke N. HinoharaE. Ideguchi T. IsobeY. Ito D.G. JenkinsY. Kawada N. KobayashiY. Kondo R. KrückenS. Kubono G. Lorusso T. NakanoT. Nakatsukasa M. Kurata-NishimuraH.J. Ong S. OtaZs. Podolyák H. SakuraiH. Scheit K. SteigerD. Steppenbeck K. SugimotoK. Tajiri S. TakanoA. Takashima T. TeranishiY. Wakabayashi P.M. WalkerO. Wieland H. Yamaguchi 《Physics letters. [Part B]》2011,704(4):270-275
18.
Excitation function and mean projected recoil ranges of nuclei produced in the7Li and16O induced reactions on51V target were measured by conventional stacked foil and thick-target thick-recoil-catcher technique for bombarding energiesE ≤ 50.0 MeV for7Li ions andE ≃ 60.0-96.0 MeV for the16O ions. The measured recoil ranges are converted to momentum transfer. The momentum transfer information was used to get clues
about some aspects of the interaction such as complete and incomplete fusion reaction mechanism which correspond to full and
reduced momentum transfer respectively. The measured excitation functions are compared with the calculation based on the statistical
model which describes only equilibrium decay of the compound nucleus using the CASCADE code. The comparison of the CASCADE
code with the measured excitation functions for the residue radioisotopes51Cr and54Mn for the7Li +51V system indicates the reaction mechanisms is complete fusion of7Li with the target nucleus51V. Similarly the comparison of the CASCADE code with the measured excitation functions of the residue radioisotopes for the
system16O +51 V indicates that the four reaction mechanisms (i) complete fusion of16O, (ii) incomplete fusion of12C, (iii) incomplete fusion of8Be and (iv) incomplete fusion of4He respectively with the target might be contributing to reaction cross sections. 相似文献
19.
High-resolution spectra of the 0–9, 0–10 and 0–11 bands of theA
2II
u
—X
2II
g
system of (16O18O)+ ion have been studied for their rotational structure. This study enables a direct determination of the Λ-doubling parameters
of theA
2II
u
andX
2II
g
states. The model of ‘pure precession’ explains, though not entirely, the Λ-doubling of theX
2II
a
state as arising out of its interaction with theB
2
Σ
g
− state. The Λ-doubling in theA
2II
u
state was found insignificant. 相似文献
20.
Optical absorption, thermoluminescence glow and emission spectra of RbBr:Ca2+ and RbBr:OH− have been studied and analysed. It is observed that both Ca2+ and OH− ions enhance theF-centre concentration.F
Z1 band in RbBr:Ca2+ appears at 1.55 eV. TL glow peak corresponding toF
Z1 centre on analysis gives a trap depth of 0.84 eV. OH− ions in the crystal seem to act as TL ‘killers’. Spectral distribution of emission under the glow peaks shows five bands
around 1.5, 1.8, 2.1, 2.5 and 2.9 eV. Probable models of TL mechanism are suggested to explain the observed TL emission bands. 相似文献