Delta Excitation in the Compressed Finite Nucleus 90Zr

Constrained spherical Hartree-Fock (CSHF) calculations under radial compression are presented for 90Zr in a model space consisting of nine major oscillator shells. An effective baryon-baryon interaction which includes the Δ resonances is used. The nucleon-nucleon (N-N) interaction is Reid Soft Core (RSC) potential. The sensitivity of the results to the choice model space is examined. It is found that the nuclear system becomes more compressible when the model space is increased. The radial density and the number of Δs are decreased by increasing model space. The results suggest that the behavior of single particle energies is independent of the model space.

DETERMINATION OF MOLECULAR BONDLENGTH BY σ~*-RESONANCE POSITION

Recently near-edge X-ray absorption fine structure (NEXAFS) has become an important method for surface structure analysing because it offers the information of intramolecular bond-length and molecular orientation for molecule adsorbate-substrate systems.

Delta Excitation in Compressed Neutron-Rich Double Magic Spherical Finite Nucleus ^(132)Sn

The ground state properties of 132Sn at equilibrium and at large compression are investigated,within the framework of the radially constrained spherical Hartree-Fock(CSHF)approximation.The delta resonance effects on the properties of neutron-rich double magic spherical nucleus,132Sn,in its ground state and the state under static compression are studied.The sensitivity of the nucleon size and Δ model spaces is investigated.At equilibrium,mixing between nucleon and Δ's in the largest model space of nine major nucleon shells plus 10 Δ orbitals was found.Expanding the nucleon model space has a larger effect on reducing the static compression modulus and softe-ning the nuclear equation of state than increasing the number of Δ states.It was found that the most of the increase in the nuclear energy generated under compression is used to create the massive Δ particles.For 132Sn nucleus under compression at 12 times the normal nuclear density,the excited nucleons to Δ's increased sharply up to 13% of the total number of constituents.This result is consistent with the values extracted from relativistic heavy-ion collisions.The single particle energy levels calculated and their behaviors under compression are examined too.A good agreement between results with effective Hamiltonian and the phenomenological shell model for the low lying single-particle spectra is obtained.

Delta Excitation Calculation Studies in Compressed Finite Spherical Nucleus ^(40)Ca

With an oscillator basis,the nuclear Hamiltonian is defined in a no-core model space.It consists of an effective nucleon-nucleon interaction obtained with Brueckner theory from the Reid soft core interaction,a Coulomb potential,nucleon-delta transition potentials,and delta-delta interaction terms.By performing spherical Hartree-Fock(SHF) calculations with the realistic baryon Hamiltonian,the ground state properties of 40Ca are studied.For an estimate of how the delta degree of freedom is excited,SHF calculations are performed with a radial constraint to compress the nucleus.The delta degree of freedom is gradually populated as the nucleus is compressed.The number of Δ's is decreased by increasing model space.Large amount of the compressive energy is delivered to create massive Δ in the nucleus.There is a significant reduction in the static compression modulus for RSC static compressions which is reduced by including the Δ excitations.The static compression modulus is decreased significantly by en larging the nucleon model space.The results suggest that inclusion of the delta in the nuclear dynamics could head to a significant softening of the nuclear equation of state.