scholarly journals 0+ States of 8Be

1968 ◽  
Vol 21 (3) ◽  
pp. 239 ◽  
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.

Multiconfiguration pair-density functional theory for doublet excitation energies and excited state geometries: the excited states of CN

2017 ◽  
Vol 19 (44) ◽  
pp. 30089-30096 ◽  
Author(s):  
Jie J. Bao ◽  
Laura Gagliardi ◽  
Donald G. Truhlar
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Excited States ◽  
Density Functional ◽  
Excitation Energies ◽  
Functional Theory ◽  
Pair Density

MC-PDFT is more accurate than CR-EOM-CCSD(T) or TDDFT when averaged over the first four adiabatic excitation energies of CN.

The 16O(p, γ)17F Direct Capture Cross Section with an Extrapolation to Astrophysical Energies

1975 ◽  
Vol 53 (17) ◽  
pp. 1672-1686 ◽  
Author(s):  
H. C. Chow ◽  
G. M. Griffiths ◽  
T. H. Hall
Keyword(s):  
Elastic Scattering ◽  
Excited States ◽  
Cross Section ◽  
Cross Sections ◽  
Capture Cross Section ◽  
Scattering Cross Section ◽  
Scattering Data ◽  
Capture Cross ◽  
Scattering Cross ◽  
Elastic Scattering Cross Section

The cross section for the direct radiative capture of protons by 16O has been measured relative to the proton elastic scattering cross section for energies from 800 to 2400 keV (CM). The elastic scattering cross section was normalized to the Rutherford scattering cross section at 385.5 keV. The capture cross section for the reaction 16O(p,γ)17F, which plays a role in hydrogen burning stars, has been extrapolated to stellar energies using a theoretical model which gives a good fit to the measured cross sections. The model involves calculation of electromagnetic matrix elements between initial and final state wave functions evaluated for Saxon–Woods potentials with parameters adjusted to fit both elastic scattering data and binding energies for the ground and first excited states of 17F. Cross sections for capture to the 5/2+ ground and 1/2+ first excited states of 17F in terms of astrophysical S factors valid for energies ≤ 100 keV have been found to be: S5/2+ = (0.317 + 0.0002E) keV b (± 8%); S1/2+ = (8.552 − 0.353E + 0.00013E2) keV b (± 5%).

scholarly journals El Decay of the First Excited State of 9Be

1984 ◽  
Vol 37 (3) ◽  
pp. 267 ◽  
Author(s):  
FC Barker
Keyword(s):  
Excited State ◽  
R Matrix ◽  
Channel Radius ◽  
First Excited State ◽  
Reasonable Choice

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.

scholarly journals Effect of Excited-state Decays on the Measured Angular Distribution of the 12C(g, p)11B Reaction

1974 ◽  
Vol 27 (3) ◽  
pp. 301 ◽  
Author(s):  
Judith M Dixon ◽  
MN Thompson
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Excited States ◽  
Cross Section ◽  
Proton Decay ◽  
Small Cross Section

The angular distribution of photoprotons from i2e as measured directly and as deduced from the inverse reaction are compared. A discrepancy is revealed; it is resolved by proposing a small cross section for proton decay to excited states of 11 B. The size

The first excited state of 9Be

1983 ◽  
Vol 61 (10) ◽  
pp. 1371-1373 ◽  
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.

scholarly journals Calculation Of The 12C+a Capture Cross Section at Stellar Energies

1971 ◽  
Vol 24 (4) ◽  
pp. 771 ◽  
Author(s):  
FC Barker
Keyword(s):  
Cross Section ◽  
Capture Cross Section ◽  
Phase Shifts ◽  
Capture Cross ◽  
R Matrix ◽  
Channel Radius ◽  
S Factor ◽  
Scattering Phase ◽  
Scattering Phase Shifts

The 12C(0:, y) 160 cross section is calculated at stellar energies, using R-matrix parameters obtained by fitting consistently the 12C+", scattering phase shifts and the ",-spectrum from 16N f:l-decay. This limits the 12C+", channel radius to the range 5-7 fm. The S-factor at Eo< = 400 keV is calculated to lie in the range 0�05-0,33 MeV.b.

scholarly journals Experimental Investigation and R-matrix Analysis of Low-lying Levels in 5He and 5Li

1988 ◽  
Vol 41 (4) ◽  
pp. 525 ◽  
Author(s):  
CL Woods ◽  
FC Barker ◽  
WN Catford ◽  
LK Fifield ◽  
NA Orr
Keyword(s):  
Matrix Analysis ◽  
Scattering Data ◽  
Matrix Formalism ◽  
Satisfactory Description ◽  
Model Calculations ◽  
R Matrix ◽  
Channel Radius ◽  
Direct Reactions ◽  
Method Of Production ◽  
Parameter Values

The ~cle-unstable nuclei SHe and Su have been studied via the 4He<,U,6U)SHe and 4He( Li,6He)SU stripping reactions at beam energies of 50 MeV and the 6U(12C, 13N)SHe and 6Li(13C, 14C)SU pickup reactions at 90 MeV. The experimental data clearly demonstrate a dependence of the lineshapes on the method of production of the mass-5 nuclei (in this case pickup or stripping). The observed lineshapes were analysed using the R-matrix formalism in a two-level approximation for each r value, with parameter values deduced from fits to the available 4He + nucleon scattering data. A best channel radius of 5�5 � 1� 0 fm was determined from the stripping data, and the corresponding set of R-matrix parameters also provided a satisfactory description of the pickup data. This channel radius is significantly larger than that employed in most previous analyses. Properties of the lowest ~ - and ! - sta~s of SHe and sU, observed via direct reactions, ate deduced from the parameter values. These properties are compared with results from earlier experimental analyses and the inferred properties of positive-parity states are compared with the results of recent shell-model calculations.

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

1992 ◽  
Vol 45 (6) ◽  
pp. 749 ◽  
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.

Excited states of acrolein: abinitio model studies on α,β-unsaturated carbonyl compounds

1982 ◽  
Vol 60 (5) ◽  
pp. 601-606 ◽  
Author(s):  
Katherine Valenta ◽  
Friedrich Grein
Keyword(s):  
Excited State ◽  
Excited States ◽  
Carbonyl Compound ◽  
Carbonyl Compounds ◽  
Excitation Energies ◽  
Vertical Excitation ◽  
Model Studies ◽  
Unsaturated Carbonyl Compound ◽  
Vertical Excitation Energies

As an explanation of the stereochemistry of photoaddition between α,β-unsaturated carbonyl compounds and olefins, Wiesner suggested that the excited state of the α,β-unsaturated carbonyl compound is pyramidal at the β-carbon. It is shown by abinitio SCF and CI studies that for acrolein in the 1nπ*, 3nπ*, and 3ππ* excited states the β-carbon remains planar. In addition, vertical excitation energies for the 1nπ* and 1ππ*, and adiabatic excitation energies for the 1nπ* and 3nπ* states of trans-acrolein have been calculated.

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