Robuta

https://pubs.rsc.org/en/content/articlelanding/2012/ce/c2ce25811k Dependence of the solid-state photomechanical response of 4-chlorocinnamic acid on crystal shape... The photochemical dynamics of crystals composed of 4-chlorocinnamic acid (4Cl-CA), whose photochemistry is dominated by an irreversible [2+2] photodimerization... the solid state