Continuous-wave Doppler-free two-photon spectroscopy of the $\mathsf{4d^{10}5s}$ $\mathsf{^{2}}$S $\mathsf{_{1/2}\rightarrow 4d^{9}5s^{2}}$ $\mathsf{^{2}}$D $\mathsf{_{3/2}}$ transition in atomic silver

Abstract.

The frequencies of the hyperfine components of the transition $4d^{10}5s ^{2}S_{1/2} \rightarrow 4d^{9}5s^{2}$ ² D _3/2 in ¹⁰⁷Ag and ¹⁰⁹Ag have been determined using Doppler-free two-photon laser spectroscopy of a thermal atomic beam and heterodyne calibration with respect to a molecular iodine line 111R(18-1) near 520 THz. For the centre of gravity of a mixture of natural abundance, we deduce the value 1 040 706 327(3) MHz. For the isotope shift, we obtain $\nu(^{109}{\rm Ag})-\nu(^{107}{\rm Ag}) = + 599.6(2)$ MHz. We find the magnetic hyperfine splitting constants of the excited state to be A(¹⁰⁷Ag (²D _3/2)) = -315.9(2) MHz and A(¹⁰⁹Ag (²D _3/2)) = -363.3(2) MHz, an order of magnitude improvement over previous authors [W. Fischer et al. , Z. Phys. 238, 249 (1970)].