ICD is characterized by its decay rate or the lifetime of the excited state. The decay rate depends on the interatomic (intermolecular) distance of A and B and its dependence allows to draw conclusions on the mechanism of ICD. Particularly important is the determination of the kinetic energy spectrum of the electron emitted from subunit B which is denoted as ICD electron. ICD electrons are often measured in ICD experiments. Typically, ICD takes place on the femto second time scale, many orders of magnitude faster than those of the competing photon emission and other relaxation processes.