A shutter system could then be used to physically separate {HEAD ~ the non affected molecules} taking advantage of {TAIL ~ this difference} in velocity 
A shutter system could then be used to physically separate { HEAD ~ the non affected molecules } taking advantage of { TAIL ~ this difference } in velocity
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH