First observation of the 4d10 5s 2S{1/2} → 4d2 5s2 2D{3/2} transition by Doppler-free two-photon spectroscopy in a silver atomic beam

We have measured the frequencies of the hyperfine components of the transition ⁴d¹⁰ 5s ²S_1/2 rarr 4d⁹ 5s^{2 2}D_3/2 in ¹⁰⁷Ag and ¹⁰⁹Ag, by Doppler-free two-photon laser spectroscopy of a thermal atomic beam and heterodyne calibration with respect to a molecular iodine line near 520 THz. We deduce the value 1 040 706 327 (3) MHz for the centre of gravity of a mixture of natural abundance. For the isotope shift, we obtain nu(¹⁰⁹Ag)-nu(¹⁰⁷Ag)=+599.6 (2) MHz. We find the magnetic hyperfine splitting constants of the excited state to be A(¹⁰⁷Ag(²D_3/2))=-315.9 (1) MHz and A(¹⁰⁹Ag(²D_3/2))=-363.3(1) MHz, an order of magnitude improvement over previous authors.