Guest dynamics as a function of pressure in a barocaloric coordination framework

Coordination framework materials tend to be mechanically soft, so their order-disorder phase transitions can be exploited, for instance, in environmentally friendly barocaloric refrigeration. Yet understanding the origin of the entropy change across these phase transitions is exceptionally challenging. QENS provides a unique way to simplify this problem by separating entropy due to dynamic site-hopping from that due to vibration or static disorder. In this experiment we will load a coordination framework, TPrAMn(dca)3, with exceptionally high barocaloric coefficient into a new TAV6 pressure cell on OSIRIS and selectively measure the dynamics of the guest tetrapropylammonium ion as a function of applied pressure. Our results will elucidate the origin of this material's functionality and help towards designing new barocaloric frameworks that display still greater barocaloric effects.