 stopping {TAIL ~ the depositing} of Al when sufficient atoms of {HEAD ~ Al} have been deposited to form the desired Al monolayer 
stopping { TAIL ~ the depositing } of Al when sufficient atoms of { HEAD ~ Al } have been deposited to form the desired Al monolayer
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH