High pressure optical studies of intermolecular interactions in low-dimensional molecular crystals

High pressure studies have a long history, yet they have been a rather specialized niche activity. The availability of commercial high pressure chambers and the progress in optical and structural probes are changing all this, and an increasing number of papers is appearing. This highlight focuses on the effect of pressure on the physical properties and phase transitions of low-dimensional molecular crystals, a class of materials where the role of weak intermolecular interactions has yet to be fully understood. To illustrate the relevance of spectroscopic and structural studies under pressure, three classes of organic molecular crystals are considered, with the common ground of high anisotropy and low-dimensionality, namely: charge transfer (CT) co-crystals exhibiting valence instabilities, quasi-one-dimensional di-substituted anthracenes, and high mobility organic thin-film transistors.