Minimal Theory of Isomerism -Q.Q and Other Interactions

TL;DR

This paper develops a minimal shell model using quadrupole-quadrupole interactions to predict nuclear isomerism, discussing its effectiveness and limitations, and extends the model with additional empirical interactions across different shells.

Contribution

It introduces a simplified, one-parameter shell model for predicting nuclear isomerism and explores its extension with empirical interactions in various nuclear shells.

Findings

Q.Q interaction predicts isomerism locations effectively.

Limitations of the Q.Q model are identified.

Empirical interactions improve predictions in specific shells.

Abstract

We perform shell model calculations using a quadrupole-quadrupole interaction (Q.Q) in single a j shell space. We show that this one-parameter interaction is a good predictor of where nuclear isomerism occurs and where it does not occur. The limitations of this interaction are also discussed. We then include other interactions e.g. in the f_{7/2} shell those obtained from the (local) spectrum of a 2 particle system and then from a 2 hole system. In the g_{9/2}where there is insufficient empirical data from the 2 hole system and so various empirical interactions are used.