Line shapes and intensities of self-broadened O ) band transitions measured by cavity ring-down spectroscopyWe present high-resolution line-shape and line-intensity measurements of self-broadened Otransitions measured using the frequency-stabilized cavity ring-down spectroscopy technique under relatively low pressure conditions. We give line-shape parameters describing collisional broadening and shifting, and we treat line narrowing in terms of Dicke narrowing or the speed dependence of collisional broadening. We indicate the importance of the line-narrowing effect which, if neglected, changes the experimentally determined collisional broadening coefficients by up to 48%. We report measured line intensities with relative uncertainties below 0.7% and compare these measurements to published data.

We present a system of two independent strontium optical lattice standards probed with a single shared ultra-narrow laser. The absolute frequency of the clocks can be verified by the use of Er:fiber optical frequency comb with the GPS-disciplined Rb frequency standard. We report hertz-level spectroscopy of the clock line and measurements of frequency stability of the two strontium optical lattice clocks.

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We present experimental values of the electron impact coherence parameters (EICP) and reduced Stokes parameters for excitation of 51P1 state of cadmium atoms. The results have been obtained using electron–photon coincidence technique for incident electron energies 80 eV and 60 eV and electron scattering angles in the range of 5° to 50°. We also present an additional set of data for electron energy 100 eV and scattering angle 50° which complements our previous results. All the experimental values are compared with theoretical relativistic distorted-wave approximation (RDWA) calculations. The first Born approximation (FBA) predictions of the alignment angle are also presented. The theoretical results are in good qualitative agreement with the experimental data.