Element- and enantiomer-selective visualization of ibuprofen dimer vibrations.

In chemistry, biology and materials science, the ability to access interatomic interactions and their dynamical evolution has become possible with the advent of femtosecond lasers. In particular, the observation of vibrational wave packets via optical (UV-visible-IR) spectroscopies has been a major achievement as it can track the motion of nuclei within the system. However, optical spectroscopies only detect the effect of the interatomic vibrations on the global electronic surfaces. New tuneable, pulsed and polarized sources of short-wavelength radiation, such as X-Ray Free electron lasers, can overcome this limitation, allowing for chemical and, of primary importance in biochemistry, enantiomeric selectivity. This selectivity may be complemented by taking into account the chemical shifts of atoms belonging to different molecular moieties