Improvements and Testing Practical Expressions for Photon Strength Functions of E1 Gamma-Transitions

TL;DR

This paper develops a modified analytical expression for E1 photon strength functions that accounts for low-energy enhancements due to nuclear structure effects, specifically the coupling between low-energy states and giant dipole resonances.

Contribution

It introduces a closed-form model incorporating coupled damped states to better describe E1 PSF, tested on spherical nuclei data sets.

Findings

The model captures low-energy enhancement effects.

Coupling between LES and GDR significantly influences PSF shape.

Validated against experimental data for spherical nuclei.

Abstract

Analytical expression for the E1 photon strength functions (PSF) is modified to account for the low-energy enhancement due to nuclear structure effects (presence of low-energy state (LES)). A closed-form expression of the E1 PSF function includes response of two nuclear states: LES and giant diplole resonance (GDR). Expression for the nuclear response function on electromagnetic field is based on a model of excitation of two coupled damped states. These approach is tested for different data sets for spherical nuclei. Impact on PSF shape of coupling between LES and GDR excitations is considered.