  Laser-induced electron diffraction is an evolving tabletop method, which aims
to image ultrafast structural changes in gas-phase polyatomic molecules with
sub-{\AA}ngstr\"om spatial and femtosecond temporal resolution. Here, we
provide the general foundation for the retrieval of multiple bond lengths from
a polyatomic molecule by simultaneously measuring the C-C and C-H bond lengths
in aligned acetylene. Our approach takes the method beyond the hitherto
achieved imaging of simple diatomic molecules and is based upon the combination
of a 160 kHz mid-IR few-cycle laser source with full three-dimensional
electron-ion coincidence detection. Our technique provides an accessible and
robust route towards imaging ultrafast processes in complex gas phase molecules
with atto- to femto-second temporal resolution.

Atomic Physics