Single-molecule femtochemistry: molecular imaging at the space-time limit.

Through a combination of light and electron probes, it may be possible to record single-molecule dynamics with simultaneous sub-Ångstrom spatial and femtosecond temporal resolution. Single-molecule femtochemistry is becoming a realistic prospect through a melding of laser spectroscopy and electron microscopy techniques. The paper by Lee et al. in this issue of ACS Nano takes a significant step toward chemical imaging at the space-time limit of chemical processes. By imaging electroluminescence spectra of single porphyrin molecules with submolecular resolution, the authors extract the implicit femtosecond dynamics of the coupled electron orbital-molecular skeletal motion triggered by a reduction-oxidation scattering process.