Infrared lattice dynamics in negative thermal expansion material in single-crystal ScF3.Simple cubic 'open' perovskite ScF3 stands out among trifluoride materials in its large, isotropic negative thermal expansion (NTE), but also its proximity of its zero-temperature state to a structural phase transition.  In this way, we identify an optically-allowed pathway to excite soft modes provides a means to athermally populate modes associated with NTE in ScF3.
THERM