Collisional broadening and shift data for even parity states of neutral barium are presented. A two-photon absorption technique is used to populate Rydberg states of nd 1 D 2 , 3 D 2 and 1 S 0 series. High-resolution Ba excitation spectra were measured using a diode detector while scanning the frequency of an excimer pumped dye laser. Inert gases Ar, Kr and Xe were used as perturbers at pressures ranging from 10 mb to 400 mb. Shifts and broadenings of spectral lines were measured as a function of pressure and principal quantum number n. Several perturbations and deviations from expected results are discussed in this paper.

Shift and broadening parameters for doubly excited states of 5d6d, 5d7d, 5d7s, 5d8s and 6p2 configurations in neutral barium atoms are presented. A tunable dye laser pumped by an excimer laser was used to populate the Rydberg states of Ba by two-photon absorption from the 6s2 1S0 ground state. Inert gases Ar, Kr and Xe at 100 mbar pressure were used as perturbing gases. The resulting line shapes were fitted to a Voigt line shape function, from which shift and broadening parameters were inferred.

An excimer pumped dye laser was used to measure collisional shift and broadening rates of the nd 1D2 (n = 4–50) and ns 1S0 series (n = 5–30) of calcium Rydberg states. Two-photon absorption techniques were used to populate the Rydberg states. High-resolution Ca excitation spectra were measured using a diode detector while scanning the frequency of the dye laser. Inert gases Ar, Kr and Xe were used as perturbers at pressures of 100 mbar. Shifts and broadenings of spectral lines were measured as functions of the principal quantum number n. The pressure-dependence behaviour of the 4s63d 1D2 Rydberg state as well as its configuration interactions is discussed.