STM study of energy-storing photoactive organometallic molecules

(Fulvalene)tetracarbonyldiruthenium (FvRu$_{2}$(CO)$_{2})$ molecules store light energy through photoisomerization. UV illumination of molecules in solution or in the solid state results in a conformational change to a high-energy photoisomer. Upon mild heating the molecule reverses to its original structure, liberating $\sim $1.3 eV. Many potential future applications of this molecule involving light energy storage requires understanding its switching behavior in a device geometry, i.e., at a surface. We have investigated self-assembly and switching behavior of FvRu$_{2}$(CO)$_{2}$ molecules on Au(111) using scanning tunneling microscopy at cryogenic temperatures and we will report on these studies.