  The ultrafast structure dynamics and surface transient electric field, which
are concurrently induced by laser excited electrons of an aluminum nanofilm,
have been investigated simultaneously by the same transmission electron
diffraction patterns. These two processes are found to be significantly
different and distinguishable by tracing the time dependent changes of electron
diffraction and deflection angles, respectively. This study also provides a
practical means to evaluate simultaneously the effect of transient electric
field during the study of structural dynamics under low pump fluence by
transmission ultrafast electron diffraction.
