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