A scattering theory method is used to treat the one-dimensional problem of a particle simultaneously acted upon by an attractive potential and by a constant electric field. Effective phaseshifts are obtained; Stark shifts and broadening of energy levels are easily calculated.
Effective range theory, taking into account the polarisation interaction, is used for the extrapolation of the phaseshifts for the scattering of electrons by heavy alkali atoms to the region of thermal energies. The phaseshifts obtained are used for the calculation of impact broadening and the shift of Rydberg levels by alkali perturbers in the ground state. The parameters of the theory obtained from the ab initio calculations give a good description of the data on broadening and shift in the case of K and Rb. In the case of Cs the parameters have to be somewhat modified to give an agreement with experiment. The phaseshifts are also used for the calculation of the width and shift in the free-electron spin-resonance frequency due to collisions with heavy alkali atoms. The results of calculations are in good agreement with experimental data. The results for total and momentum transfer cross sections for the scattering of electrons with energies from 10 -4 to 10 -1 eV by K, Rb and Cs atoms are presented.
A Rydberg atom has a highly excited valence electron which is weakly bound and far from the nucleus. These atoms have exaggerated properties that make them attractive candidates for quantum computation and studies of fundamental quantum mechanics. The discrete energy levels of Rydberg atoms are shifted in the presence of an electric field by the Stark effect and are similarly shifted due to a magnetic field by the Zeeman effect. These effects couple the energy levels together, creating avoiding crossings. At these avoided crossings, an electron in one energy level can jump to the other. Our goal is to be able to use these avoided crossings to put the electron in a superposition state of both energy levels. In order to achieve this we created new software that enables us to calculate the energy levels of an electron in both a magnetic and an electric field. We present energy level maps visualizing the results of the Stark and Zeeman effects.