Quantum width and shift of spectral lines in the non-impact regime

A general quantum-mechanical theory of the perturbation shift and broadening of spectral lines in the non-impact regime has been extended and programmed and applied to two simple potentials—the square-well potential and a Morse potential. At low pressure, the non-impact and impact line shapes coincide, whereas at high pressures the non-impact line has acquired an asymmetry, a slight relative shift, and a width about twice that of the impact line.