{HEAD ~ A solid material} or combination of materials is evaporated in {TAIL ~ the chamber} to form vapor 
{ HEAD ~ A solid material } or combination of materials is evaporated in { TAIL ~ the chamber } to form vapor
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH