核心概念
The authors compute the magnetic dipole (M1) γ-ray strength functions for odd-mass neodymium and samarium isotopes using the shell-model Monte Carlo method. They identify a low-energy enhancement (LEE) in the M1 γ-ray strength functions of these nuclei, which was recently observed experimentally in some of them.
摘要
The authors use the shell-model Monte Carlo (SMMC) method in combination with the static-path approximation (SPA) and the maximum-entropy method (MEM) to calculate the M1 γ-ray strength functions for the odd-mass neodymium isotopes 143-151Nd and samarium isotopes 147-153Sm.
Key highlights:
- They quantify the statistical uncertainties in the calculated M1 γ-ray strength functions, which are under control for the excitation energies relevant to experiments despite a Monte Carlo sign problem.
- They identify a low-energy enhancement (LEE) in the M1 γ-ray strength functions of these odd-mass lanthanides, which was recently observed experimentally in some of them.
- They also find a scissors mode resonance (SR) in the strongly deformed isotopes and a spin-flip mode.
- They observe that the decrease in the LEE strength with neutron number along an isotopic chain is compensated for by an increase in the SR strength in the deformed nuclei.
- They compare their results with recent experiments, finding overall agreement for the neodymium isotopes but the calculated LEE strength is smaller than the experimental values for the samarium isotopes.
統計資料
The average excitation energy Ei and temperature T at which the M1 strength functions are calculated for each odd-mass isotope are provided.