Collisional shifts and broadenings of the 4sns 1S0 and 4snd 1D2 Rydberg series of calcium perturbed by inert gases

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.