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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1969

Finite element formulation for linear thermoviscoelastic materials

Report presents the finite difference equations in time and finite element matrix equations in space for general linear thermovisoelastic problems. The equations are derived for a general three-dimensional body but are applicable to one- and two-dimensional configurations with minor changes.

Chen, J. C.↗
NASA NTRS1969

H-H interaction potentials.

Direct Coulomb interaction matrix elements between hydrogen atoms in ground states calculated, presenting interaction potential

Flannery, M. R.↗
NASA NTRS1969

Nonadiabatic translations in polyatomic molecules

Matrix elements of nonadiabatic perturbation emphasized in semiempirical theory for evaluating polyatomic molecules radiationless rate constants in terms of electronic-vibrational state

Young, J. H.↗
NASA NTRS1971

Inelastic transition densities

Inelastic scattering transition densities in single particle operator reduced matrix elements between initial and final nuclear states for nucleon angular momentum calculations

Braley, R. C.↗
NASA NTRS1971

Deformed Brueckner-Hartree-Fock calculation for light nuclei

For the first time the Brueckner-Hartree-Fock (BHF) method was applied to nuclei whose intrinsic structure is nonspherical. One aim was to investigate whether the energy dependent reaction matrix calculated from a realistic nucleon-nucleon interaction leads to deformations similar to, or different from, those obtained from energy independent interactions in Hartree-Fock (HF) calculations. Reaction matrix elements were calculated as a function of starting energy for the Hamada-Johnston interaction, using a Pauli operator appropriate to O-16 and a shifted oscillator spectrum for virtual excited states. Binding energies, single-particle energies, radii, and shape deformations of the intrinsic state in unrenormalized as well as renormalized BHF are discussed and compared with previous HF studies. Results are presented for C-12, O-16, and Ne-20.

Braley, R. C.↗
NASA NTRS1972

Short-range correlations in carbon-12, oxygen-16, and neon-20: Intrinsic properties

The Brueckner-Hartree-Fock (BHF) method has been applied to nuclei whose intrinsic structure is nonspherical. Reaction matrix elements were calculated as functions of starting energy for the Hamada-Johnston interaction using the Pauli operator appropriate to O-16 and a shifted oscillator spectrum for virtual excited states. Binding energies, single particle energies, radii, and shape deformations of the intrinsic state, in ordinary as well as renormalized BHF, are discussed and compared with previous HF studies and with experiment when possible. Results are presented for C-12, 0-16 and Ne-20. It is found that the binding energies and radii are too small, but that separation energies are well reproduced when the renormalized theory is used.

Braley, R. C.↗
NASA NTRS1972

Kinematic distributions for electron pair production by muons

Cross sections and kinematic distributions for the trident production process plus or negative muon plus charge yields plus or minus muon plus electron plus positron plus charge (with charge = dipion moment and Fe) are given for beam energies of 100 to 300 GeV at fixed (electron positron) masses from 5 to 15 GeV. This process is interesting as a test of quantum electrodynamics at high energies, and in particular as a test of the form of the photon propagator at large timelike (four-momentum) squared. For this purpose, it is desirable to impose kinematic cuts that favor those Bethe-Heitler graphs which contain a timelike photon propagator. It is found that there are substantial differences between the kinematic distributions for the full Bethe-Heitler matrix element and the distributions for the two timelike-photon graphs alone; these differences can be exploited in the selection of appropriate kinematic cuts.

Linsker, R.↗