title: The 31S0-33P0 transition in the aluminum isotope ion 26A1+: a potentially superior passive laser frequency standard and spectrum analyzer.
abstract: The aluminum 26 isotope ion is proposed here as a possible candidate for a superior atomic clock. For this even isotope, the extraordinarily long lifetime of the 33P0 state offers a potential clock transition (31S0-33P0) linewidth of 300 microHz. The mF = 0 --> 0 transition has only a quadratic Zeeman shift approximately 4 x 10(-18) at 0.1 Gauss magnetic field, compared to approximately 10(-8) for the hydrogen maser. Electronic quadrupole moments vanish for both J and J' states and with them shifts due to electric field gradients. All shifts have been estimated and are orders of magnitude less than for Hg+ and Ba+, which are being studied as atomic clock elements.
authors.affiliation: Department of Physics, University of Washington, Seattle, WA 98195, USA.
authors.forename: N
authors.initials: N
authors.lastname: Yu
authors.forename: H
authors.initials: H
authors.lastname: Dehmelt
authors.forename: W
authors.initials: W
authors.lastname: Nagourney