Excitations of Atoms and Broadening of Spectral Lines

Atomic excitation and spectral line broadening

Multiply-excited atoms and line broadening

Natural broadening of atomic spectral lines in the presence of energy-level superposition

Doubly-excited atoms and the line broadening.

Theory of Resonance Broadening of Spectral Lines by Atom-Atom Impacts

Natural broadening of atomic spectral lines and generalized operator of electromagnetic interaction.