High-precision Spatiotemporal Imaging of Molecular Rotational Wave Packets

Abstract

For deeper understanding and better use of a dynamic nature of molecules, it is essential to clearly visualize molecular motions of interest. Because motions of molecules are generally described by wave packets, coherent superpositions of stationary state wave functions, it is of great importance to experimentally characterize wave packets. Time-resolved Coulomb explosion imaging is one of the powerful approaches for achieving this objective. However, there have been several difficulties in existing imaging techniques. High-precision measurements of molecular movies were, therefore, still limited. Here, we developed a conceptually new, space-slice ion imaging apparatus to overcome existing difficulties, offering a way to capture molecular snapshots in the polarization plane of an incident laser pulse. We applied our method to real-time imaging of laser-kicked rotational wave packet dynamics. In the observed molecular movies, wave packet dynamics including localization and dispersion during the classical-like rotational motion are clearly visualized. Such an experimental characterization of a spatiotemporal pattern of wave packet dynamics leads to direct physical insight into molecular motions.