Image courtesy of Ohio State University
Electron momentum energy map of an oxygen (O2) molecule.
The energy of a molecule's own electron, ejected by an intense ultra-fast laser pulse and scattered back towards the molecule, has been used to capture freeze-frame images of atoms vibrating in oxygen and nitrogen molecules with femtosecond (10-15 seconds) resolution in a technique called laser-induced electron diffraction.
The laser-induced electron diffraction technique offers a novel method for capturing the ultrafast motion of atoms within a molecule through the manipulation of one of its own electrons. Imaging the dynamics of atoms within molecules with high spatial and temporal resolution offers the potential to better understand and control chemical reactions.
Developments in theory and ultrafast lasers are rapidly advancing our ability to observe and control the motions of atoms and electrons within molecules undergoing chemical transformations. BES-supported scientists at Ohio State University and Kansas State University recently reported the first freeze-frame images of atoms in vibrating oxygen and nitrogen molecules by using the molecule’s own electrons to report the positions of its atoms with exquisite spatial (0.1 Å) and femtosecond (10-15 sec) temporal resolution. The technique, called laser-induced electron diffraction (LIED), uses the oscillating electromagnetic field of an intense, ultra-fast laser pulse to pull an electron from the molecule in a process known as photo-ionization and then hurl that same electron back to interact with and diffract from the molecular ion. The diffraction pattern from the re-scattered electron provides a snapshot of the molecular structure at the instant when it interacts with the atoms in the molecule. The LIED technique offers a novel method for capturing the ultrafast motion of atoms within a molecule through the manipulation of one of its own electrons.
Ohio State University
Office of Science Basic Energy Sciences (BES) program
C.I. Blaga, et al., “Imaging ultrafast molecular dynamics with laser-induced electron diffraction,” Nature 483 194 (2012). [DOI: 10.1038/nature10820]
Nature News & Views, Nature 483, 161 (2012).