PUMP-PROBE DIFFRACTION IMAGING OF VIBRATIONAL WAVE-FUNCTIONS

The theory of pump-probe diffraction experiments shows that probabilit y density distributions of vibrational wave functions are experimental ly observable. In the experiment a laser prepares a molecule in a sele cted vibrational state, in either the same or a different electronic m anifold. The diffraction pattern of the molecule in the excited state is the Fourier transform image of the nuclear probability density dist ribution, as determined by the vibrational eigenfunction of the molecu le. This suggests the possibility to directly observe components of mo lecular vibrational wave functions. Model calculations illustrate the concept on iodine molecules, and sodium dimers. The relevance to time- resolved pump-probe experiments that prepare vibrational wave packets is discussed. (C) 1998 American Institute of Physics.