Collision broadening and molecular orbital X-rays

The decay of an inner-shell vacancy in an ion moving through a dense target is considered. Collisions with target atoms perturb the atomic energy levels which gives rise to a broadening of the X-ray line and the possibility of emission from transient molecular levels. The emission spectrum is calculated for a model system and shows good qualitative agreement with recent experiments. It is demonstrated that the transmission of X-ray detector windows can have a profound effect on the shape and position of observed emission from molecular levels.