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1.
High spin states of 57Co have been studied via prompt γ-ray spectroscopy in the reactions 48Ti(12C, p2n) and 54Fe(α, p) at 26–48 MeV and 12–24 MeV, respectively. The energies and decay modes of these levels were determined from the analysis of γ-ray singles and γ-γ coincidence spectra, excitation functions, angular distributions and correlations. The relevant lifetimes were measured by the Doppler-shift attenuation method. The new levels established in this work are at 4037, 4814 and 5918 keV with the most probable Jπ assignment of , if and , respectively. The previously known level at 2524 keV was assigned to have . These together with the known (1224 keV) and (1690 keV) levels constitute the yrast states of 57Co. The measured lifetimes of the above six levels are (in order of increasing energies) 0.085±0.030, 0.32±0.10, 0.16±0.06, 0.10?0.07+0.06, 1.5?0.54 and 0.17?0.07+0.08 ps, respectively. Comparisons with some theoretical calculations are presented. 相似文献
2.
Resonances in the reaction 56Fe(p, γ)57Co have been surveyed over the energy range 1.2 ? Ep ? 1.5 MeV wherein the analogues of the ground state state and 0.136 MeV state of 57Fe are expected to occur. Gamma-ray angular distributions have been used to establish resonance and bound-state spins, and decay schemes have been determined. The analogue resonances appear to be severely fragmented, however the density of resonances of a given spin correlates quite well with (3He, d) results and with the expected analogue-state positions. 相似文献
3.
A. Filevich A. Ceballos M.A.J. Mariscotti P. Thieberger E. Der Mateosian 《Nuclear Physics A》1978,295(3):513-524
The 6? and 7? isomeric states in 66Ga and 68Ga at 1440.9 and 1229.6 keV, respectively, have been populated with the (13C, 2np) and (15N, n2p) reactions on natural Fe. The half-lives of these states have been measured to be and . Using previous data on the hyperfine field of Ga in Fe, the g-factors of these states have been determined by means of the TDPAD method. The results are and . These values are in very good agreement with the independent particle model if one assumes the and configurations and uses the empirical proton and neutron g-factors from odd-A neighboring nuclei instead of the Schmidt values. The large disagreements with experiment when Schmidt values are used show that core polarization effects are important in these nuclei. 相似文献
4.
Sugimitsu Tsuyoshi 《Nuclear Physics A》1974,224(1):199-220
Excitation functions of γ-rays from the 75As(p, n)75Se reaction were measured with 2.0 to 3.6 MeV protons to establish the level scheme of 75Se up to about 1.5 MeV excitation energy. Internal conversion electrons following the same reaction were measured at 4.5 and 5.0 MeV proton energy. Using theoretical predictions of the statistical compound nucleus model together with deduced internal conversion coefficients, unique spin assignments were obtained for the and levels. Probable spins were proposed to the for one of the doublet and or for the other), 579.4 or , or and or levels. Alow-lying level was tentatively assigned at 133.2 keV energy. It was found that a low-lying level which appears systematically in other odd Se nuclei is absent in 75Se. 相似文献
5.
L.K. Fifield T.J.M. Symons C.H. Zimmerman M.J. Hurst F. Watt K.W. Allen 《Physics letters. [Part B]》1977,68(2):125-128
Levels at 7.17, 8.29, 8.96 and 9.88 MeV in 19F have been assigned spin and parity , , and , respectively, from resonance strength and γ-ray angular distribution measurements employing the 15N(α,γ) 19F reaction. An earlier assignment of to the 8.96 MeV level is incorrect. The measured properties of the states are compared with the results of both SU (3) shell model and cluster model calculations. 相似文献
6.
P.M. Heinen J.J. Engelen E.W. Kittel W.J. Metzger M.M. Schouten J.S.M. Vergeest R.T. Van De Walle B. Jongejans H. Voorthuis M. Cerrada R.J. Hemingway S.O. Holmgren M.J. Losty 《Nuclear Physics B》1977,122(3):443-463
A partial-wave analysis of the low-mass (π+π?p) system produced in the reaction K?p → K?(π+π?p) at 4.2 GeV/c incident momentum is performed in order to study the two (π+π?p) enhancements around 1500 and 1700 MeV. It is found that the low-mass (π+π?p) system can be described using the spin-parity states and only. In the 1500 MeV region contributions are observed from the wave decaying into p? and the wave decaying into Δ++π?; in the 1700 MeV region contributions are found from the wave decaying into Δ++π?, the wave decaying into p?, and the wave decaying into p?. 相似文献
7.
The cw dye laser excitation spectrum of the vibronic transition of the CCN radical was observed between 21 205 and 21 335 cm?1 with the Doppler-limited resolution, 0.04 cm?1. The CCN radical was produced by reaction of microwave discharged CF4 with CH3CN. The observed spectrum was analyzed to determine rotational and centrifugal constants and effective spin-orbit and spin-rotation coupling constants for both the and the states, and also the Λ-type doubling constants for the state. The constants determined reproduce the observed spectrum with an average deviation of 0.0027 cm?1, and are considered to be precise enough for predicting the ground-state microwave transition frequencies. No evidence was found for perturbation in either the or the state. 相似文献
8.
E. Arai M. Futakuchi H. Kamada J. Komaki T. Matsuzaki M. Ogawa Y. Oguri 《Nuclear Physics A》1982,378(2):259-272
Using a proton beam with an overall resolution of 300–400 eV (FWHM) spins, parities and partial widths were determined for all resonances observed (99 s-wave, 42 p-wave, 106 d-wave and one g-wave resonances). Differential cross sections for proton elastic scattering from 56Fe were measured at proton energies between 3.1 and 4.2 MeV. Spectroscopic factors and Coulomb displacement energies were extracted for the fragmented analogue resonances which correspond to the , and states in 57Fe. A value of the s-wave proton strength function was deduced. 相似文献
9.
C.W. Cottrell 《Nuclear Physics A》1973,204(1):161-171
Some of the low-lying energy levels of 107Ag and 109Ag were excited by Coulomb excitation using α-particles from 4.8 to 7.2 MeV. Transitions to the isomeric state (), involving a parity change, were observed both directly in the singles spectra and indirectly by the decay of the isomer. The isomer in both silver isotopes was populated by transitions from the level, which was strongly excited. The observed branching ratio in 109Ag for the transition was (0.315 ± 0.09) % and for the transition was (0.055±0.03) %. The total rate of populating the level from the level was (0.215±0.04) % in 107Ag. The level schemes have been discussed on the weak-coupling model, allowing admixtures of singleparticle wave functions to account for the weaker transitions. 相似文献
10.
C.P. Bust J.R. Carter W.W. Neale J.G. Rushbrooke D.R. Ward R.E. Ansorge B.Y. Oh M. Pratap G. Sionakides G.A. Smith J. Whitmore R. Raja L. Voyvodic 《Nuclear Physics B》1978,140(3):409-422
We have investigated the reactions . The final state is dominated by diffractive production of a system which shows a strong tendency to form . The process is also observed in this reaction, indicating an energy dependence of s?1.5±0.1. The channel shows less single diffraction, and has a doubly diffractive component consistent with pomeron factorization. Strong Δ++(Δ++) production is agoain seen, but in contrast to the channel we also observe considerable ?0 production. 相似文献
11.
Angular distributions of the vector analyzing power and the absolute cross section were measured for the 58Ni(d, p)59Ni reaction at a deuteron energy of 10 MeV. The observed j-dependence of the vector analyzing power allowed unambiguous spin assignments for the following states in 59Ni with excitation energies in ; ; . The data are well reproduced by DWBA calculations employing deuteron and proton optical model parameters obtained from analyses of elastic scattering cross sections and polarizations. A tentative spin assignment of is made for the level at 3.061 MeV. A assignment to the level at 3.538 MeV is suggested on the basis of the empirical behavior of the j-dependence of the vector analyzing power for l = 2 transitions. Measurements of the vector analyzing power for the four low-lying 59Ni states formed by l = 1 transfer were made for angles from 2.5° to 15° using a magnetic spectrograph. A very strong j-dependence was observed for these far-forward-angle measurements in agreement with DWBA predictions. 相似文献
12.
Form factors for inelastic electron scattering for the excitation of the , , , and members of the ( configuration in 51V are studied by considering the effect of configuration mixing in the shell model. The inclusion of the highly excited configurations which does not contribute to the γ-transitions is shown to give rise to significant modifications of the form factors in large momentum transfer regions. Under the assumption of the static central potential as the residual interactions between protons, good agreement with the experimental data on form factors is obtained by the ordinary force as well as smaller effective charges than the bare charge for higher multipole transitions. 相似文献
13.
Electromagnetic studies have established that the ground state doublet in 7Li is well described by the LS coupling shell model, provided quadrupole effective charge is introduced. The results of microscopic calculations for the excitation of the level in inelastic proton scattering shown within indicate that an equivalent renormalization of the 7Li quadrupole neutron transition densities is also necessary. This verifies the assumption which was made in a previous calculation of the cross section for the excitation of the level in the 7Li+24Mg reaction. 相似文献
14.
The quadrupole interaction for the state of 197Hg in solid Hg was observed by the e?-γ time differential perturbed angular correlation method. The quadrupole coupling constant νQ=126 (2) MHz is derived. By comparison with experimental quadrupole coupling constants for 199Hg in Hg and HgCl2 as well as for 201Hg in HgCl2 the quadrupole moment of the state in 197Hg is related to that of the 201Hg ground state, which is known. The value is deduced. This value is not in agreement with the assumption of a shell-model configuration for the 134 keV state. It is consistent with an interpretation of the level in terms of the core coupling model of de Shalit. 相似文献
15.
G. Tarrago M. Dang-Nhu G. Poussigue G. Guelachvili C. Amiot 《Journal of Molecular Spectroscopy》1975,57(2):246-263
High resolution spectra of the ν3 band of methane, 12CH4, were recorded by using a “third generation vacuum Fourier interferometer”; a large pressure range (from 0.009 to 10 Torr) with a sample path fixed at eight meters was used, enabling observation of transitions with intensity ratios as low as . More than 350 forbidden transitions of the ν3 band, including about 125 transitions of the Q+ branch, were unambiguously identified. Of the 277 transitions retained for computations, one-hundred have 11 ≤ J ≤ 16. From combination difference relations using pairs of transitions having the same upper state energy level (forbidden-allowed and forbidden-forbidden pairs were used), 276 independent differences between ground state energy levels could be determined with uncertainties of about 0.001 cm?1.These data yielded the following values for the ground state structure constants of 12CH4 along with their standard deviations (in cm?1): , , , , , , Thus, for the first time, the scalar constant π0 has been evaluated and ir values have been obtained for the two tetrahedral constants ?0 and ξ0; furthermore, these values are in very good agreement with the ones recently determined from radiofrequency data, i.e., in cm?1: , , From these values, the 276 differences can be reproduced with an overall rms deviation equal to 0.0009 cm?1.Finally, the ground state energies of 12CH4 have been calculated for J ≤ 16. 相似文献
16.
R.J. Hemingway R. Armenteros C. Dionisi Ph. Gavillet A. Gurtu S.O. Holmgren M.J. Losty J.C. Marin M. Mazzucato L. Montanet M. Banting R. Blokzijl A.J. De Groot B. Jongejans J.C. Kluyver W.M. Van Leeuwen G.G.G. Massaro J. Wells 《Nuclear Physics B》1978,142(3):205-219
Forty events have been observed in a large (133 events/βb) experiment at 4.2 GeV/c incident K? momentum. Thirty nine of the events come from the three-body reaction . The is mainly produced in the forward hemisphere (direction of the incident K?). The lifetime is measured to be τ = (0.75 +0.14?0.11 × 10?10 sec substantially less than the Particle Data Group value of (1.3 ?0.3+0.2) × 10?10 sec. The mass is determined to be 1671.7 ± 0.6 MeV, in good agreement with other determinations. The decay asymmetry parameter α (for the decay mode ) is found to be ?0.2 ± 0.4. 相似文献
17.
D. Mertin R. Tischler A. Kleinrahm R. Kroth H. Hübel C. Günther 《Nuclear Physics A》1978,301(3):365-381
High spin states in 191, 192, 193, 195, 197, 199Hg were investigated by observing γ-rays and conversion electrons in the compound reactions . In 197Hg the decoupled band built on the state and the semi-decoupled negative-parity band are observed up to , respectively. A careful investigation of 199Hg revealed no new high spin states above the previously known levels with ?. Half-lives were determined for the 10+, 7?, 8? and 16? states in 192Hg, the if (frc states in 191, 193, 195, 197Hg. The systematics of the level energies and B(E2) values for the positive-parity ground and bands and the negative-parity semi-decoupled bands in 190–200Hg is discussed. 相似文献
18.
The one-quasiparticle bands in the N = 99 nucleus 171Hf have been identified to spins of about using (heavy ion, xn) reactions. The moments of inertia of these bands are consistent with the absence of backbending in the N = 98 core nucleus. The half-life of the intrinsic state was measured as 63.6 ns. The strength of the transition is discussed. Two three-quasiparticle isomers with spins and parities have been identified and their suggested configurations are a neutron added to the 6+ and 8? two-quasiproton states of the core. The moment of inertia of a rotational band based on the isomer supports this suggestion, and shows the effect of partial rotation alignment of the neutron. 相似文献
19.
The half-lives of the states at 522.6 and 393.9 keV in 113Cd and 115Cd have been determined to be 0.322±0.012 and 0.75± 0.03 ns, respectively. Values of the ) and the energy difference in odd Cd (A = 113–119) are compared with those in neighbouring even Cd. The level properties are interpreted in the framework of the triaxial rotor model. 相似文献
20.
W. Dünnweber E.R. Cosman E. Grosse W.R. Hering P. von Brentano 《Nuclear Physics A》1975,247(2):251-273
A γ-decay scheme for levels in 209Pb up to 4.13 MeV of excitation has been established by means of the reaction 208Pb(d, pγ)209Pb. In high efficiency p-γ coincidence measurements γ-cascades have been observed from the single-particle states and from core-excited states with very small single-particle strength. Assuming a qualitative validity of the weak-coupling model spins and main configurations of particle-core states can be deduced from their γ-decay. The members of the multiplet could be located. A systematic manner of doublet splitting is found for the lowest states with main configuration . A new decay branch of the single-particle state is attributed to an admixture of quadrupole core vibration. 相似文献