# Study of the long-lived excited state in the neutron deficient nuclides $^{195,197,199}$Po by precision mass measurement

## TL;DR

This study uses precision mass measurements to determine the excitation energies of isomeric states in neutron-deficient polonium isotopes, confirming their isomeric nature across different neutron numbers.

## Contribution

It provides new, precise excitation energies for specific isomeric states in polonium and related isotopes, enhancing understanding of nuclear energy systematics in this region.

## Key findings

- Confirmed the isomeric nature of $13/2^{(+)}$ states across isotopes.
- Determined excitation energies for isomeric states in $^{195,197,199}$Po.
- Extended energy systematics in neutron-deficient nuclei.

## Abstract

Direct mass measurements of the low-spin $3/2^{(-)}$ and high-spin $13/2^{(+)}$ states in the neutron-deficient isotopes $^{195}$Po, $^{197}$Po, and high-spin $13/2^{(+)}$ state in $^{199}$Po were performed with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE-CERN. These measurements allow the determination of the excitation energy of the isomeric state arising from the $\nu$i$_{13/2}$ orbital in $^{195,197}$Po. Additionally, the excitation energy of isomeric states of lead, radon, and radium isotopes in this region were obtained from $\alpha$-decay chains. The new excitation energies complete the knowledge of the energy systematics in the region and confirm for the first time that the $13/2^{(+)}$ states remain isomeric, independent of the number of valence neutrons.