at least one photosensitizer which is effective to promote free radical polymerization through {HEAD ~ bimolecular photochemical reactions} of the energy donor type, {TAIL ~ the hydrogen abstraction type}, or by formation of a donor acceptor complex with monomers or additives leading to ionic or radical species; and 
of
at least one photosensitizer which is effective to promote free radical polymerization through { HEAD ~ bimolecular photochemical reactions } of the energy donor type , { TAIL ~ the hydrogen abstraction type } , or by formation of a donor acceptor complex with monomers or additives leading to ionic or radical species ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH