The role of repulsive forces in the shape of collision-broadened spectral lines and in the output of gas lasers

The shape of a collision-broadened spectral line taking into account an interatomic potential that includes both repulsive and attractive forces is obtained, in the impact approximation, using Anderson´s formulation. Results for the lineshape, shift, broadening, and asymmetry are given for a general potential of the inverse power law form and for the Lennard-Jones potential. It is shown that inclusion of repulsive forces leads to results that exhibit experimentally observed behavior of the shift and asymmetry of a collision-broadened line in a range of conditions. Some comparison of experimental results and theoretical estimates for the 0.63-μ line of²⁰Ne in a³He-²⁰Ne discharge and in a²⁰Ne discharge at laser-operating conditions are given.