Resonantly enhanced ns and nd Rydberg spectroscopy of sodium

Abstract

We report new observations of photodissociation and ionization in sodium vapour by using a Nd:YAG pumped dye laser and a thermionic diode as an ion detector employing two experimental geometries. In the first experiment, single photon dissociation of a sodium dimer into an excited atomic state followed by a one-photon excitation to even parity Rydberg states of atomic sodium has been investigated. In the second arrangement, we used a two-colour two-step excitation process which yields much higher Rydberg members of the even parity ns 2S1/2 and nd 2D3/2,5/2 series. The relative intensities of the ns and nd members of the Rydberg series are attributed to the spatial overlap between the 3p and ns and nd wavefunctions, evidenced by the ab initio single configuration Hartree-Fock calculations.