Low-lying energy levels of ^{229}Th35+ and the electronic bridge process

TL;DR

This paper investigates the electronic bridge process in ^{229}Th^{35+} to accurately determine the nuclear transition frequency, which is crucial for nuclear clock development and understanding fundamental constants.

Contribution

It provides the first detailed calculations of low-lying energy levels of ^{229}Th^{35+} and estimates the electronic bridge process probability to refine the nuclear transition frequency.

Findings

Calculated energies of low-lying states with uncertainties.

Estimated probability of the electronic bridge process.

Implications for precise nuclear clock development.

Abstract

The nuclear transition between the ground and the low-energy isomeric state in the ^{229}Th nucleus is of interest due to its high sensitivity to a hypothetical temporal variation of the fundamental constants and a possibility to build a very precise nuclear clock, but precise knowledge of the nuclear clock transition frequency is required. In this work we estimate the probability of an electronic bridge process in ^{229}Th^35+, allowing to determine the nuclear transition frequency and reduce its uncertainty. Using configuration interaction methods we calculated energies of the low-lying states of Th^35+ and determined their uncertainties.