2025 Volume 19 Issue 1 Pages A0137-
Real-time observation of molecular and electronic dynamics is one of the ultimate goals of molecular science, enabling deeper insight into chemical reactions. Ultrashort laser pulses, typically with femtosecond pulse durations, provide a powerful means for visualizing molecular and electronic motions during chemical reactions in real time. In addition to their ultimate time resolution, femtosecond laser pulses offer extremely high peak intensities exceeding the Coulomb force between electrons and ion cores in molecules. Such intense laser fields induce a variety of nonlinear phenomena, including tunneling ionization, electron rescattering, high-order harmonic generation, multiple-ionization, and Coulomb explosion. This account highlights recent applications of ultrashort intense laser pulses to the visualization of complex molecular dynamics, including the roaming reaction of formaldehyde, and molecular orbital shapes, even revealing their asymmetric distribution. Furthermore, I elucidate the mechanisms underlying the selective scission of identical chemical bonds in CO2, paving the way toward coherent control of molecular reactivity.
