Observation by two-photon laser spectroscopy of the 4d¹⁰5s  ²S_1/24d⁹5s^2  2D_5/2 clock transition in atomic silver

We report the observation of the very narrow 4d¹⁰5s  ²S_1/24d⁹5s^2  2D_5/2 transition in atomic silver. The frequencies of the hyperfine components in ¹⁰⁷Ag and ¹⁰⁹Ag have been measured using Doppler-free two-photon laser spectroscopy of a thermal beam and heterodyne calibration with respect to the a₁ component of the 62P(4-5) line in molecular iodine near 661  nm. For the center of gravity of a mixture of natural abundance, we deduce the value 906  641  295.77(19)  MHz. For the isotope shift, we obtain (¹⁰⁹Ag)−(¹⁰⁷Ag)=564.15(37)  MHz, from which we deduce the frequency and isotope shift of the 4d¹⁰5s  ²S_1/24d¹⁰6p  ²P_3/2 transition at 206  nm.

©2006 The American Physical Society