Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
T he form ula for th e energy levels o f th e rigid ro ta to r h as been a p p lied to nuclei. Two kin d s of nuclear ro ta tio n are discussed: th e ro ta tio n o f th e whole nucleus leads to a n A~l re la tio n for th e energy levels of different n u clei; th e ro ta tio n a ro u n d th e nucleus leads to a n relation. B o th relations are based on th e a ssu m p tio n of eq u al d en sity of different nuclei. E xam ples for b o th relatio n s hav e been found.T he existence of sim ple ra tio n a l relatio n s betw een th e e x c ita tio n levels of a nucleus, p redicted b y th e ro ta to r form ula a n d em pirically know n in som e h e av y nuclei, h as been confirm ed in o th er nuclei.T he value of th e ro ta tio n c o n sta n t h as been d eterm in ed : B0 = 5 064 MeV.The system of ro ta to r levels a p p ears to be rele v a n t to th e in te rp re ta tio n of th e observed nuclear levels.T he tra n sitio n p robabilities in a sy stem o f ro ta to r levels is discussed. N u clear e x c ita tio n levels are com pared w ith X -ra y levels. F ro m th e level system can be concluded th a t th e nu clear rad ii fulfil th e relatio n r = r0Ab w ith r 0 = 2*03! 10~13 cm. T his v alue is in co nform ity w ith values found by o th e r m ethods.Twenty years ago, Ellis (1922) suggested, for the first time, a system of discrete nuclear energy levels for describing the origin of a system of y-rays. He discussed the applicability of the combination rule for these rays and w rote: ' The general results lend support to the view th a t stationary states exist in the nucleus and it is hoped th a t by investigating the gamma-rays of other radioactive bodies some general principles in the arrangement of nuclear levels may be found.' The assumption of the existence of discrete nuclear excitation levels was confirmed later on by the observation of the fine structure of a-rays and of corresponding well-defined y-rays. Measurements of the energy release in artificial nuclear reactions indicated the occasional excitation of nuclei in these reactions and pro vided more data for nuclear levels. But the hope of finding some general principles for the values of nuclear levels has not been fulfilled up to now.The quantum mechanical prediction of nuclear energy levels is not possible as long as the law of interaction between the particles which constitute the nucleus is not known. On the assumption of an exponential law, levels of light nuclei have been calculated by Feenberg and Wigner and others, and general considerations on the symmetry of the Hamiltonian allowed some inferences as to the possible grouping and spacing of energy levels (cf. Wigner & Feenberg 1941). It is not possible to say that these predictions have so far been fulfilled (cf. Margenau 1941). Bohr & Kalckar (1937) showed th at vibrations of the whole nucleus should vary as A~i , w h e r e A is the atomic weight, and th at at least the lowest known levels do not correspond to vibrations of this kind. Vibrations of the surface should lead to higher energy levels th...
The excitation of curve for B ll (d,p) has been obtained by observing the intensity of the beta-rays from B 12 as a function of bombarding voltage from about 0.3 to 1.85 Mev. No resonance structure was observed in this region of bombardment. The yield at 1.47 Mev is approximately 10 7 beta-rays/microcoulomb of deuterons.The short-range protons which are formed in the above reaction were also observed in photographic plates, and range measurements showed that the Q-value of the reaction is 0.15 Mev. It is believed that this value does not represent the formation of B 12 in its ground state, however, but in an excited state at about 1.1 Mev. A group believed to be protons of higher energy (corresponding to Q=1.25 Mev) but of much lower intensity was subsequently observed.It was shown, by bombardment of enriched B 10 and of normal boron, that a gamma-ray of approximately 1.1 Mev energy is associated with the disintegration of B 11 by deuterons. It is therefore almost certain that this gamma-ray arises from the decay of B 12 to its ground state. Intensity measurements also indicate that this is the case.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.