Photoassociation spectroscopy of cold He(2(3)S) atoms

We observe vibrational states by photoassociation spectroscopy of cold He(2 3S) atoms. Photoassociation resonances are detected as peaks in the Penning ionization rate over a frequency range of 20 GHz below the atomic 2 3S1-2 3P2 transition frequency. We have observed three vibrational series, of which two can be identified. A possible mechanism to explain the observed increase of the Penning ionization rate is discussed

Comparison of theoretical and experimental red and near infrared absorption spectra in overheated potassium vapour

The K2 molecular spectra have been theoretically and experimentally investigated in the wavelength range between 550 nm and 1100 nm and at the temperatures between 650 K and 1100 K. Semiclassical theoretical simulations were performed using the most recent data for the potential energy curves for the K(4S)+K(4S) and K(4S)+K(4P) systems and the relevant dipole transition moments. The measurements of the corresponding spectra were performed by a spatially resolved absorption method in an inhomogeneous overheated potassium vapour generated in a heat pipe. Both theoretical and experimental investigations confirmed that the reduced absorption coefficients of the potassium diffuse triplet bands at 575 nm, 721.5 nm and 1095 nm are practically independent of temperature in a wide temperature range. The obtained data for the reduced absorption coefficients of these bands can be used for a simple and accurate determination of potassium atom number densities in the range from $5\times 10^{16}$ cm-3 to $5\times 10^{18}$ cm-3