Localization in Rotational Excitation of Diatomic Molecules Induced by a Train of Optical Pulses

We theoretically investigate the localization of population distribution in rotational excitation of diatomic molecules induced by a train of optical pulses in the terahertz region. In a simulation with parameters of real molecules, the localization is observed as a combined effect of several causes. For mathematical analysis, we classify the localization into four types based on the viewpoints of physical processes. We provide some extreme numerical examples of the four types of localizations.