Ultrafast dynamics of shock waves in polymers and proteins: The energy landscape

A 4.5 GPa shock pulse producing a cycle of compression heating (<25 ps) and expansion cooling (∼1.5 ns) is used to study fast mechanical dynamics of solid organic polymers and proteins. Coherent Raman spectroscopy of a dye in the sample shows that compression occurs by an instantaneous part followed by a second, ∼300 ps, structural relaxation process. After expansion, a mechanically distorted structure is produced which does not relax on the <15 ns time scale. The results are interpreted with an energy landscape model.