Year: 2013
Type: article
Abstract: Using resonant two-step laser excitation of trapped ${}^{232}$Th${}^{+}$ ions, we observe 43 previously unknown energy levels within the energy range from $7.3$ to $8.3$ eV. The high density of states promises a strongly enhanced electronic bridge excitation of the ${}^{229m}$Th nuclear state that is expected in this energy range. From the observation of resonantly enhanced three-photon ionization of Th${}^{+}$, the second ionization potential of thorium can be inferred to lie within the range between 11.9 and 12.3 eV. Pulsed laser radiation in a wide wavelength range from 237 to 289 nm is found to provide efficient photodissociation of molecular ions that are formed in reactions of Th${}^{+}$ with impurities in the buffer gas, leading to a significantly increased storage time for Th${}^{+}$ in the ion trap.
Source: Physical Review A
Institution: Physikalisch-Technische Bundesanstalt
Language: Latvian
Topic: Atomic and Molecular Physics
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2002170741