Surface-induced rotational isomerism within solid 1,3-diiodopropane thin films

Two unique solid–solid phase transitions within 1,3-diiodopropane (DIP) frozen thin films grown on a Pt(111) single crystal were observed by infrared and thermal desorption spectroscopies. Three distinct structural phases were indeed identified upon annealing the DIP films from 100 to 215 K, namely, an abrupt conformational isomerization change about 180 K and a separate molecular axis reorientation around 200 K. These DIP crystal structural and orientational changes were found to be driven by a template effect induced by the metal surface.