Note that there is a 1 √ N "dilution" factor (normalization factor) in V +A j . For the FGR type of estimation of rate constant, this results in a 1/N normalization factor which often causes difficulties in theoretically observing any collective modification for polariton photophysics dynamics or in VSC rate constant changes. Nevertheless, we shall see that the collective PMET rate can naturally avoid such a pitfall. The total rate constant k +{A} ≡ ∑ N j=1 k +A j between the |+⟩ state and all possible acceptor states {|A j ⟩} can be expressed as