Ultrafast modulation of electronic structure by coherent phonon excitations.

ABSTRACT: Femtosecond x-ray absorption spectroscopy with a laser-driven high-harmonic source is used to map ultrafast changes of x-ray absorption by femtometer-scale coherent phonon displacements. In LiBH₄, displacements along an Ag phonon mode at 10 THz are induced by impulsive Raman excitation and give rise to oscillatory changes of x-ray absorption at the Li K-edge. Electron density maps from femtosecond x-ray diffraction data show that the electric field of the pump pulse induces a charge transfer from the BH4- to neighboring Li⁺ ions, resulting in a differential Coulomb force that drives lattice vibrations in this virtual transition state.

SUBMITTER: Weisshaupt J 

PROVIDER: S-EPMC11015475 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature