In a path breaking discovery ,an international team of scientists led by groups from the Max Planck Institute of Quantum Optics (MPQ) in Garching, Germany, and from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and the University of California at Berkeley has used ultrashort flashes of laser light to directly observe the movement of an atom’s outer electrons for the first time.Through a process called attosecond absorption spectroscopy, researchers were able to time the oscillations between simultaneously produced quantum states of valence electrons with great precision. These oscillations drive electron motion.

read here