Bibliographic Details
| Title: |
Laser Mössbauer spectroscopy of 229Th in CaF2. |
| Authors: |
Hiraki, Takahiro, Masuda, Takahiko, Takatori, Sayuri, Schaden, Fabian, Bartokos, Michael, Beeks, Kjeld, Fukunaga, Yuta, Grüneis, Andreas, Guan, Ming, Kazakov, Georgy, LaGrange, Thomas, Leitner, Adrian, Morawetz, Ira, Ogake, Ryoichiro, Okai, Koichi, Pimon, Martin, Pressler, Martin, Riebner, Thomas, Sasao, Noboru, Schneider, Felix |
| Source: |
Science; 8/20/2026, Vol. 393 Issue 6813, p795-799, 5p |
| Subject Terms: |
Thorium, Calcium fluoride, Solid state physics, Selection rules (Nuclear physics), Mössbauer spectroscopy, Atomic clocks, Electric fields |
| Abstract: |
Mössbauer spectroscopy is widely used in chemistry, geology, and solid-state physics to probe the local physical and chemical environment of nuclei in materials. Here, we extended this technique into the optical range using a vacuum ultraviolet laser to probe the low-energy nuclear transitions of thorium-229 (229Th) doped in calcium fluoride (CaF2) crystals. We discovered four distinct doping sites for the thorium ions, determined the characteristic electric field gradients emerging from the interaction with the host crystal, and identified the microscopic structure of the two dominant configurations. Site-selective laser excitation enabled the study of the isomeric state lifetime and laser-induced quenching for all sites. This technique provides a powerful probe of the nuclear environment, yielding foundational data for designing future solid-state nuclear clocks. Editor's summary: Atomic clocks are the world's most precise timekeepers, but nuclear clocks, which depend on transitions between nuclear energy levels, might prove even more useful. Scientists have long focused on a particular nucleus, that of thorium-229, because its transitions are compatible with laser frequencies. Particularly promising are solid-state nuclear clocks in which thorium nuclei are embedded within a solid such as calcium fluoride. However, the presence of electric field gradients inside the solid leads to the splitting of nuclear energy levels. Hiraki et al. performed laser Mössbauer spectroscopy of the nuclear clock transitions of thorium-229 doped into calcium fluoride single crystals. Based on the spectra, the researchers identified four distinct doping sites for thorium ions within the crystal and characterized their distinct electric field environments. —Jelena Stajic [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |