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Parity-Projected Shell Model Monte Carlo Level Densities for fp-shell Nuclei

C. Özen·K. Langanke·G. Martinez-Pinedo·D. J. Dean
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Abstract

We calculate parity-dependent level densities for the even-even isotopes 58,62,66 Fe and 58 Ni and the odd-A nuclei 59 Ni and 65 Fe using the Shell Model Monte Carlo method. We perform these calculations in the complete fp-gds shell-model space using a pairing+quadrupole residual interaction. We find that, due to pairing of identical nucleons, the low-energy spectrum is dominated by positive parity states. Although these pairs break at around the same excitation energy in all nuclei, the energy dependence of the ratio of negative-to-positive parity level densities depends strongly on the particular nucleus of interest. We find equilibration of both parities at noticeably lower excitation energies for the odd-A nuclei 59 Ni and 65 Fe than for the neighboring even-even nuclei 58 Ni and 66 Fe.

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C. Özen, K. Langanke, G. Martinez-Pinedo, D. J. Dean. 2007-03-26. Parity-Projected Shell Model Monte Carlo Level Densities for fp-shell Nuclei. https://doi.org/10.1103/physrevc.75.064307

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