In this in the Experimental Physical Chemistry Program of the Chemistry Division, Chronister will test theoretical models of the dynamics of molecular solids. A combination of high pressure and ultrafast nonlinear coherent spectroscopic techniques will be used as high resolution probes of the dynamics of molecular solids at low temperatures. Ultrafast coherent Raman, photon echo, and material preparation techniques will be used to uncover the homogeneous dynamics in amorphous and pressure broadened systems. These experiments will be used to refine theories of optical and vibrational dephasing in amorphous and mixed crystalline solids. %%% Chronister will measure the behavior of solids under high pressure and low temperatures. The information gathered is difficult to obtain because the pressures involved are extremely high and temperatures are very low. However, these data will ultimately aid our understanding of the dynamic interactions between species in solid solution and their host materials.