Theory of internal conversion of the thorium-229 nuclear isomer in solid-state hosts

Abstract

Laser excitation of thorium-229 nuclei in doped wide bandgap crystals has been demonstrated recently, opening the possibility of developing ultrastable solid-state clocks and sensitive searches for new physics. We develop a quantitative theory of the internal conversion of isomeric thorium-229 in solid-state hosts. The internal conversion of the isomer proceeds by resonantly exciting a valence band electron to a defect state, accompanied by multi-phonon emission. We demonstrate that, if the process is energetically allowed, it generally quenches the isomer on timescales much faster than the isomer's radiative lifetime, despite thorium being in the +4 charge state in the valence band.

Discussions of NEET process and particle-hole interaction added

References in corpus (5)

• Frequency ratio of the ${}^{229\mathrm{m}}$Th nuclear isomeric transition and the ${}^{87}$Sr atomic clock
• ${}^{229}{\mathrm{ThF}}_4$ thin films for solid-state nuclear clocks
• Internal conversion from excited electronic states of ${}^{229}\mathrm{T}h$ ions
• Precision theoretical determination of electric-dipole matrix elements in atomic cesium
• Radiative Decay of the ${}^{229m}$Th Nuclear Clock Isomer in Different Host Materials

Cited by in corpus (2)

• ${}^{229}$Th Nuclear Spectroscopy in an Opaque Material: Laser-Based Conversion Electron Mössbauer Spectroscopy of ${}^{229}$ThO${}_2$
• Theoretical evaluation of decay mode of ${}^{229m}\mathrm{Th}$ in solid samples