scholarly journals Alpha?Particles from the Reaction 7Li(p,g)8Be(a)4He

1960 ◽  
Vol 13 (2) ◽  
pp. 116 ◽  
Author(s):  
DS Gemmell
Keyword(s):  
Ground State ◽  
Alpha Particles ◽  
Particle Spectrum ◽  
Dispersion Formula

The OI:-particle spectrum from the reaction 7Li(p,y)8Be*(0I:)4He has been determined in coincidence with y-rays_ The results indicate that, apart from the broad 2� 9 MeV level, there are no additional levels between the ground state and 7 MeV with intensities greater than 3 per cent. of the 2 . 9 MeV level. It is shown that the shape of the 2 -9 MeV level can be fitted satisfactorily by a dispersion formula if a large value for the reduced width of the level is assumed.

Linear Nuclei: A Density Functional Interpretation

1997 ◽  
Vol 06 (03) ◽  
pp. 507-513
Author(s):  
J. Kolehmainen ◽  
H. Häkkinen ◽  
M. Manninen ◽  
M. Koskinen
Keyword(s):  
Alpha Particle ◽  
Single Particle ◽  
Density Functional ◽  
Metal Clusters ◽  
Alpha Particles ◽  
Rectangular Cavity ◽  
Particle Spectrum ◽  
Functional Interpretation ◽  
Particle Interpretation ◽  
Linear Shape

We show that linear shape isomers of small even-even nuclei exist with nearly any internucleon interactions. The shapes of the linear isomers look like chains of alpha-particles, but single-particle spectrum reveals that alpha-particle interpretation is not needed. Indeed, the same shapes are obtained even with noninteracting particles in a rectangular cavity. Linear shape isomers are shown to exist also in metal clusters.

ANGULAR DISTRIBUTIONS IN GAMMA–ALPHA REACTIONS IN THE NUCLEI OF NUCLEAR EMULSIONS

1965 ◽  
Vol 43 (6) ◽  
pp. 1015-1019 ◽  
Author(s):  
Jan P. Roalsvig
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Ground State ◽  
Intensity Ratio ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Nuclear Emulsions

The angular distribution for alpha particles produced by (γ, α) reactions in the nuclei of nuclear emulsions has been measured. For the reaction 16O(γ, α)12C, in which the 12C nucleus is left in its ground state (J = 0+, T = 0), through an excited state at 12.5 MeV in 16O, the angular distribution is in agreement with a mixture of E1 and E2 interactions, with an E2/E1 intensity ratio of 0.50. For the same reaction, through an excited state at 14.3 MeV in 16O, the angular distribution is best represented by a pure E2 interaction.

EVIDENCE FOR LOW-MOMENTUM-TRANSFER PROCESS IN K41 (α,n)Sc44m,g REACTIONS FROM RANGE MEASUREMENTS OF PRODUCTS

1961 ◽  
Vol 39 (3) ◽  
pp. 697-705 ◽  
Author(s):  
Taku Matsuo ◽  
T. T. Sugihara
Keyword(s):  
Momentum Transfer ◽  
Compound Nucleus ◽  
Transfer Process ◽  
Ground State ◽  
Energy Region ◽  
Thick Target ◽  
Alpha Particles ◽  
Direct Reaction ◽  
Range Distribution ◽  
Lower Limits

Average forward ranges have been measured for the product nuclides Sc43, Sc44m, and Sc44g as produced in the reactions K41(α,xn) with alpha particles in the energy region 23 to 39 Mev. These ranges, which are determined by a thick target – thick catcher technique, indicate that the (α,n)-produced isomers are formed in part by a low-momentum-transfer process above 30 Mev, its contribution being larger for the ground-state nuclide Sc44g. From a thick target –thin catcher experiment at 40 Mev, it is found that the range distribution for Sc43 is that expected for a compound-nucleus reaction. Normalizing the Sc44m and Sc44g activity distributions to that of Sc43 for the catchers farthest from the target, we estimate the lower limits for the contribution of a direct-reaction low-momentum-transfer process to the formation of Sc44m and Sc44g at 40 Mev to be about 30% and 46% respectively.

THE ANGULAR DISTRIBUTION AND YIELD OF THE REACTION F19(p, α0)O16

1957 ◽  
Vol 35 (2) ◽  
pp. 155-167 ◽  
Author(s):  
R. L. Clarke ◽  
E. B. Paul
Keyword(s):  
Angular Distribution ◽  
Least Squares ◽  
Cross Sections ◽  
Legendre Polynomial ◽  
Ground State ◽  
Energy Region ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Method Of Least Squares ◽  
Channel Spin

The yield of the ground state alpha particles from the F19(p, α0)O16 reaction has been studied from an energy of 1.3 Mev. to 2.7 Mev. The observed angular distributions were analyzed in terms of a Legendre polynomial expansion by the method of least squares. Six resonances were found in the energy region studied, at bombarding energies of 1.358 Mev., 1.709 Mev., 1.853 Mev., 2.11 Mev., 2.31 Mev., and 2.58 Mev. The widths and peak cross sections of these resonances are respectively: (54 ± 10 kev., 46 ± 5 mb.), (140 ± 5 kev., 55 ± 6 mb.), (132 ± 5 kev., 77 ± 8 mb.), (75 ± 25 kev., 10 ± 2 mb.), (80 ± 25 kev., 32 ± 5 mb.), and (300 ± 25 kev., 51 ± 10 mb.). Their spins, parities, channel spin mixtures, and partial widths are discussed.

scholarly journals Antiadiabatic Theory of Superconducting State Transition: Phonons and Strong Electron Correlations—The Old Physics and New Aspects

2010 ◽  
Vol 2010 ◽  
pp. 1-36 ◽  
Author(s):  
Pavol Baňacký
Keyword(s):  
Superconducting State ◽  
Ground State ◽  
Cooper Pair ◽  
Chemical Potential ◽  
Correlation Energy ◽  
Real Space ◽  
Pair Formation ◽  
Particle Spectrum ◽  
Strong Electron ◽  
Nuclear Dynamics

Complex electronic ground state of molecular and solid state system is analyzed on the ab initio level beyond the adiabatic Born-Oppenheimer approximation (BOA). The attention is focused on the band structure fluctuation (BSF) at Fermi level, which is induced by electron-phonon coupling in superconductors, and which is absent in the non-superconducting analogues. The BSF in superconductors results in breakdown of the adiabatic BOA. At these circumstances, chemical potential is substantially reduced and system is stabilized (effect of nuclear dynamics) in the antiadiabatic state at broken symmetry with a gap(s) in one-particle spectrum. Distorted nuclear structure has fluxional character and geometric degeneracy of the antiadiabatic ground state enables formation of mobile bipolarons in real space. It has been shown that an effective attractive e-e interaction (Cooper-pair formation) is in fact correction to electron correlation energy at transition from adiabatic into antiadiabatic ground electronic state. In this respect, Cooper-pair formation is not the primary reason for transition into superconducting state, but it is a consequence of antiadiabatic state formation. It has been shown that thermodynamic properties of system in antiadiabatic state correspond to thermodynamics of superconducting state. Illustrative application of the theory for different types of superconductors is presented.

Ground State of Three Alpha Particles

1968 ◽  
Vol 172 (4) ◽  
pp. 1062-1064 ◽  
Author(s):  
J. R. Fulco ◽  
D. Y. Wong
Keyword(s):  
Ground State ◽  
Alpha Particles

scholarly journals PROBING PRE-FORMED ALPHA PARTICLES IN THE GROUND STATE OF NUCLEI

2011 ◽  
Vol 20 (04) ◽  
pp. 1038-1041
Author(s):  
J.A. SCARPACI ◽  
M. FALLOT ◽  
D. LACROIX ◽  
M. ASSIÉ ◽  
L. LEFEBVRE ◽  
...  
Keyword(s):  
Alpha Particle ◽  
Ground State ◽  
Short Range ◽  
Daughter Nucleus ◽  
Alpha Particles ◽  
Particle Properties ◽  
Dependent Theory ◽  
Collision Partner ◽  
Alpha Cluster ◽  
The Continuum

In this proceeding we report on alpha particle emission through the nuclear break-up in the reaction 40 Ca on a 40 Ca target at 50A MeV. It is observed that alpha particles are emitted to the continuum with very specific angular distribution during the reaction. The alpha particle properties seem to be compatible with an alpha cluster in the daughter nucleus that is perturbed by the short range nuclear attraction of the collision partner and emitted as described by a time-dependent theory. This mechanism offers new possibilities to study alpha particle properties in the nuclear medium.

STUDY OF "CONDENSATE" STATES IN 12C AND 16O BY INELASTIC SCATTERING

2008 ◽  
Vol 17 (10) ◽  
pp. 2118-2123 ◽  
Author(s):  
A. S. DEMYANOVA ◽  
A. A. OGLOBLIN ◽  
S. A. GONCHAROV ◽  
T. L. BELYAEVA
Keyword(s):  
Inelastic Scattering ◽  
Excited States ◽  
Ground State ◽  
Transfer Reaction ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Hoyle State

Study of some properties of the lowest states of 12 C , including the second 0+, 7.65 MeV (Hoyle) state by inelastic scattering of alpha-particles and 3 He were carried out. Two independent methods of measuring the radii of the short-lived excited states based on the analysis of diffraction and rainbow patterns of the angular distributions were proposed. Both methods showed that Hoyle state radius is by factor ~ 1.2 – 1.3 larger than that of the ground state. 8 Be transfer reaction was identified. The probability of L = 0 configuration in Hoyle state occurred to be 3 times larger than in the ground state indicating to the significant presence of condensate configuration in the former one.

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