Effects of nonlocality in time of interactions of an atom with its   surroundings on the broadening of spectral lines of atoms
  We investigate effects of nonlocality in time of the interaction of an atom with its surroundings on the spectral line broadening. We show that these effects can be very significant: In some cases nonlocality in time of this interaction can give rise to a spectral line splitting. 
Renat Kh. Gainutdinov, Aigul A. Mutygullina and Werner Scheid