El Decay of the First Excited State of 9Be

The E1 decay strength of the t + first excited state of 9Be is calculated using R-matrix formulae in which the excited state is correctly treated as unbound. Agreement with experiment is obtained for a reasonable choice of channel radius.

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0+ States of 8Be

Australian Journal of Physics ◽

10.1071/ph680239 ◽

1968 ◽

Vol 21 (3) ◽

pp. 239 ◽

Cited By ~ 46

Author(s):

FC Barker ◽

HJ Hay ◽

PB Treacy

Keyword(s):

Excited State ◽

Excited States ◽

Cross Section ◽

Scattering Data ◽

Excitation Energies ◽

R Matrix ◽

Channel Radius

The light even nuclei with A ;;;. 10 have 0+ excited states near 6 MeV, probably with large (X-particle reduced widths. A similar state in BBe would be very broad. Evidence for 0+ excited states in BBe has been obtained here using many-level R-matrix fits to known (X-(X scattering data, but the excitation energies depend strongly on the assumed channel radius. For a simultaneous fit to the 9Be(p, d)BBe cross section, assuming these higher states are not strongly populated, the channel radius is restricted to (7~~) fm, implying a 0+ excited state at (6=f3) MeV of width (9=f4) MeV.

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The first excited state of 9Be

Canadian Journal of Physics ◽

10.1139/p83-175 ◽

1983 ◽

Vol 61 (10) ◽

pp. 1371-1373 ◽

Cited By ~ 20

Author(s):

F. C. Barker

Keyword(s):

Excited State ◽

Cross Section ◽

Reasonable Agreement ◽

R Matrix ◽

First Excited State

An R-matrix fit to recent 9Be(γ,n)8Be cross-section measurements just above the neutron threshold gives parameters that are in reasonable agreement with those obtained from fits to data from other reactions.

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The 12C(p, g)13N Cross Section near the Ep = 0·46 MeV Peak

Australian Journal of Physics ◽

10.1071/ph920749 ◽

1992 ◽

Vol 45 (6) ◽

pp. 749 ◽

Cited By ~ 2

Author(s):

S Hinds ◽

FC Barker

Keyword(s):

Excited State ◽

Cross Section ◽

Thick Target ◽

R Matrix ◽

Best Value ◽

First Excited State ◽

Target Data

The I2C(p,'Y?3N cross section in the neighbourhood of the Ep = 0�46 MeV peak has been measured using thin and thick targets, and fitted using R-matrix formulae. The best value for the radiation width of the first excited state of I3N is 0�53�0�05 eV. eanalysis of earlier thick-target data gives values consistent with this result.

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Continuous Ultraviolet Absorption BY Si+(4Pe): an Exploratory R-Matrix Calculation

International Astronomical Union Colloquium ◽

10.1017/s0252921100107663 ◽

1988 ◽

Vol 102 ◽

pp. 185-188

Author(s):

J.A. Tully

Keyword(s):

Excited State ◽

Cross Sections ◽

Configuration Interaction ◽

Matrix Method ◽

Ultraviolet Absorption ◽

Total Cross Sections ◽

R Matrix ◽

First Excited State ◽

Matrix Calculation

AbstractThe R-matrix method is used to calculate photoionisation from the first excited state 3s3p23Pe of Si+. The lowest two triplet terms 3s3p3Poand 3p23Peof the residual ion Si++are included in the calculation. They are approximated by configuration interaction wavefunctions which are constructed from six spectroscopic orbitals: 1s,2s,2p,3s,3p,3d. Partial and total cross-sections are tabulated for photon energies ranging from threshold (705 A) up to 2.5 Ryd (365 A). Some of the 3p2np autoionising resonances are delineated and shown graphically.

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Calculation of the 13N(p, ?)14O Cross Section at Low Energies

Australian Journal of Physics ◽

10.1071/ph850657 ◽

1985 ◽

Vol 38 (5) ◽

pp. 657 ◽

Cited By ~ 15

Author(s):

FC Barker

Keyword(s):

Experimental Data ◽

Excited State ◽

Shell Model ◽

Cross Section ◽

Energy Region ◽

Model Calculations ◽

R Matrix ◽

Considerable Uncertainty ◽

First Excited State ◽

Low Energies

R-matrix formulae are used to calculate the 13N(p, ?) 140 cross section in the energy region of astrophysical interest. Values of the R-matrix parameters are determined by fitting experimental data in 14C and 14N as well as 140, and by making use of shell model calculations where necessary. With the presently available data, there is considerable uncertainty in the predicted cross section, but this could be reduced appreciably by a measurement of the lifetime of the first excited state of 14C. With the preferred channel radius of about 5 fm, the predicted cross section is lower than those found in two previous calculations, which are discussed in some detail.

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