Line-widths of pressure-broadened spectral lines

This report is mainly of a review and expository nature and has been prepared for the purpose of outlining in considerable detail the method of calculating the widths of pressure-broadened spectral lines by using the impact theory of Anderson. In section I, the general quantum mechanical result is derived. In section II the adiabatic approximations are discussed. In section III, Anderson's theory has essentially been repeated with some slight changes. In section IV, several cases of molecular interactions are treated. The calculations have been extended to include the effect of the nonresonant terms of the interaction matrix which are neglected in Anderson's work.