Electromagnetic Dipole Strength in Transitional Nuclei

TL;DR

This paper introduces a microscopic method using Instantaneous Shape Sampling to calculate electromagnetic dipole absorption in transitional nuclei, achieving excellent agreement with experimental data near the nucleon emission threshold.

Contribution

It presents a novel approach combining RPA and IBA to account for shape fluctuations in transitional nuclei for dipole strength calculations.

Findings

Excellent match with experimental absorption cross sections

Validates the Instantaneous Shape Sampling concept

Demonstrates the importance of shape fluctuations in dipole strength

Abstract

Electromagnetic dipole absorption cross-sections of transitional nuclei with large-amplitude shape fluctuations are calculated in a microscopic way by introducing the concept of Instantaneous Shape Sampling. The concept bases on the slow shape dynamics as compared to the fast dipole vibrations. The elctromagnetic dipole strength is calculated by means of RPA for the instantaneous shapes, the probability of which is obtained by means of IBA. Very good agreement with the experimental absorption cross sections near the nucleon emission threshold is obtained.