Using a frequency-doubled diode laser system, we have measured the hyperfine splitting in the (6s 2 7s)7S 1/2 excited state of the two naturally occurring thallium isotopes. For 205 Tl and 203 Tl we find frequency intervals of 12294.5͑1.5͒ and 12180.5͑1.8͒ MHz, respectively. This measurement addresses an earlier discrepancy in measured values for these intervals. At the same time, we have measured, with a factor of 50 improved precision, the 205 Tl-203 Tl isotope shift within the 378-nm 6 P 1/2 -7S 1/2 transition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.