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We report studies of examples of reflection-asymmetric nuclei which are difficult to access using compound nucleus reactions. The octupole radium isotopes withN>132 and radon isotopes are not accessible by reactions employing stable targets and beams; we have shown that multinucleon transfer reactions can populate these nuclei with sufficient yield for their structure to be determined. We report high-spin studies in218, 220, 222Rn and222, 224, 226, 228, 230Ra: these show that the Ra isotopes withA<228 have the characteristics of octupole deformed nuclei whereas the Rn isotopes behave like octupole vibrators. Measurements of theB(E1)/B(E2) ratios indicate that the electric dipole moment in these nuclei is constant with spin. The most octupole deformed nuclei are predicted to be uranium isotopes withN≈132; measurements of the very fissile nucleus226U suggest that it is octupole deformed and has a large intrinsic electric dipole moment. Finally, we speculate that the best examples of pear shapes are the hyperdeformed minima predicted to lie low in uranium isotopes withN≈140; their signature of high-multiplicity low-energyE1 photon cascades should be detectable using present-day high-efficiency germanium arrays. 相似文献
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The literature data on heteropolar and homopolar 2-center bond dissociation energies in organic molecules in the gas phase and the corresponding heats of formation of radicals and ions have been critically evaluated. Data for more than 500 bonds are represented in tabular form together with the pertinent literature references. Selected electron affinities and π-bond dissociation energies have also been incorporated. The follow-up paper will discuss some empirical general aspects of these data particularly regarding the effect of structure on the bond dissociation energies. 相似文献
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This paper considers the problem of evaluating the maximum load that an elastic–plastic frame structure can withstand when material or element softening is present. Here we propose an extension of the Linear Matching Method to take into account material softening. The technique has two major steps: reduction of the total potential energy to obtain the solution of a linear problem and scaling of the resulting mechanism of deformation to maximize the load. Two procedures are evaluated for the second of these steps; a direct approach which simply examines how the solution evolves along a radial path in degree of freedom space, and an incremental method which takes into account how the solution might evolve along paths away from this radial line. It is demonstrated that the incremental approach is more robust and provides stable solutions for high and low levels of softening, but numerical instabilities in the procedure can occur for intermediate degrees of softening. 相似文献
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R.-D. Herzberg N. Amzal J.E. Bastin F. Becker P.M.T. Brew P.A. Butler A.J.C. Chewter J.F.C. Cocks O. Dorvaux K. Eskola J. Gerl P.T. Greenlees N.J. Hammond K. Hauschild K. Helariutta F. Heßberger M. Houry A. Hürstel R.D. Humphreys G.D. Jones P.M. Jones R. Julin S. Juutinen H. Kankaanpää H. Kettunen T.L. Khoo W. Korten P. Kuusiniemi Y. Le Coz M. Leino A.P. Leppänen C.J. Lister R. Lucas M. Muikku P. Nieminen R.D. Page T. Page P. Rahkila P. Reiter Ch. Schlegel C. Scholey G. Sletten O. Stezowski Ch. Theisen W.H. Trzaska J. Uusitalo H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):205-208
In-beam conversion electron spectroscopy experiments have been performed on the transfermium nuclei 253, 254No using the conversion electron spectrometer SACRED in nearly collinear geometry in conjunction with the gas-filled separator
RITU at the University of Jyv?skyl?. The experimental setup is discussed and the spectra are compared to Monte Carlo simulations.
The implications for the ground-state configuration of 253No are discussed.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: rdh@ns.ph.liv.ac.uk
RID="b"
ID="b"Present address: GANIL, F-14021 Caen, France.
RID="c"
ID="c"Permanent address: IReS Strasbourg, IN2P3-CNRS, F-67037-Strasbourg, France.
RID="d"
ID="d"Present address: CEA/DIF DCRE/SDE/LDN F-91680 Bruyeres-le-Chatel.
RID="e"
ID="e"Present address: Daresbury Laboratory, Daresbury WA4 4AD, UK.
RID="f"
ID="f"Permanent address: IPN Lyon, IN2P3-CNRS, F-69037 Lyon, France. 相似文献
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J. J. A. Wijs G. D. Elsdon J. R. Stubbs H. Lührig H. Atkinson A. Azadian G. Spitzer F. W. Epple C. H. Manley H. S. Shrewsbury L. V. Cocks E. Nightingale L. Hoton D. W. Steuart P. Smith G. H. Leopold W. J. de Mooy G. van B. Gilmour S. H. Blichfeldt T. Thornley E. L. Smith H. P. Kaufmann E. R. Bolton und C. Revis 《Fresenius' Journal of Analytical Chemistry》1930,80(7-8):303-314
Ohne Zusammenfassung 相似文献
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H. C. Scraggs E. S. Paul A. J. Boston J. F. C. Cocks D. M. Cullen K. Helariutta P. M. Jones R. Julin S. Juutinen H. Kankaanp M. Muikku P. J. Nolan C. M. Parry A. Savelius R. Wadsworth A. V. Afanasjev I. Ragnarsson 《Nuclear Physics A》1998,640(3-4):337-361
High-spin states have been populated in 54119Xe via the 96Mo(27Al,p3n) reaction at 133 MeV, using the
γ-ray spectrometer to record triple γ-ray coincidences. The known level scheme has been significantly extended and several band crossings identified. In particular, the νh11/2 yrast band has been extended to Iπ = (83/2−) and shows features which are consistent with those of smooth band termination at high spin. Theoretical results for 119Xe at high spin are discussed within the framework of cranked Nilsson-Strutinsky calculations, together with results for 117Xe. 相似文献
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Susan Anderson Kenneth R. Seddon Raymond D. Wright Alan T. Cocks 《Chemical physics letters》1980,71(2):220-223
Room-temperature electronic absorption spectra, and emission spectra at room temperature and 77 K, have been measured for the mixed ligand 2,2'-bipyndine-2-(2-pyridyl)quuioline complexes of ruthemum (II). The charge-transfer states initially populated by absorption of visible light are essentially localised on individual ligands, and there is little coupling of these ligand states. Emissions, however, occur from a single state possessing the characteristics of the pyridylquinoline ligand alone. 相似文献
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(β-Arylethyl)phosphorochloridates decompose easily yielding 1-chloro-2-arylethanes and/or arylethylenes, presumably via the concerted P-Cl fission and the expulsion of metaphosphate-like species. 相似文献