Development of Ultrafast Spectroscopy and Reaction Mechanisms Studied by the Observation of Ultrashort-Life Species and Transition States

Ultrafast spectroscopy of coherent phonon in carbon nanotubes using sub-5-fs visible pulses

“…Optical parametric conversion has drawn scientists' great attention in last decade since tunable broad band ultrafast laser pulse in ultraviolet (UV) [1], visible and near infrared (NIR) regions can be generated. It has grown wide application area especially in ultrafast time-resolved spectroscopy.…”

Transient process spectroscopy for the direct observation of inter-molecular photo-dissociation

“…However, the coherent molecular vibrations produced by impulsive photoexcitation dephase as fast as a few picoseconds, 5,7 and moreover, the inter-molecular collision destroys the coherence of the molecular vibration. Therefore, previously it had been thought to be impossible to observe the inter-molecular reactions via coherent molecular vibration dynamics.…”

Relating transition-state spectroscopy to standard chemical spectroscopic processes

“…In general, the existence and possible role of quantum coherence in this non-ergodic motion remains a critical question [36][37][38]; quantum coherence requires much more than just ordered classical motion as the phase difference between quantum wavepackets propagating through equilibrium systems in thermal environments must also be maintained, generating quantum entanglement [39]. Not just transition states are now studied by also photochemical species existing down to ultrashort timescales with wide ranging applications in energy harvesting and catalysis, as revealed, e.g., by the works of Kobayashi [40][41][42][43][44][45][46][47][48][49][50].…”