depositing said {HEAD ~ source material} on {TAIL ~ a base} in the form of a precursor film; and 
on
depositing said { HEAD ~ source material } on { TAIL ~ a base } in the form of a precursor film ; and
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH