Self-imaging of a molecule by its own electrons

Difference between the electron scattering cross-section measured (a) and calculated (b) at R = 3.68 Å (corresponding to the outer turning point of the vibrational motion) and R = 2.78 Å (corresponding to the inner turning point of the vibrational motion) for the case of an I2 vibrational wave packet created by photo-excitation of the B-state using a visible laser with a wavelength of 555 nm. The difference in the scattering cross-sections is shown as a function of the kinetic energy of the returning electron and the angle into which the electron is scattered. Particularly near a rescattering angle of 180 degrees (i.e. for back-scattered electrons) a major difference is seen between the scattering cross-section at the geometry corresponding to the inner and outer turning point of the vibration. In other words, the time-dependent changes in the internuclear distance are recognizable in time-dependent changes of the measured electron scattering cross-sections.