This study develops a Transition-Resolved Renormalization Framework for separating intrinsic excitonic structure from environment-induced electrodynamic effects in hybrid nanocrystal–plasmonic systems. TD-DFT results for CdSe–ZnS and published atomistic-pseudopotential data for an InP reference system are used as independent electronic-structure inputs. For CdSe–ZnS, four resolved bands exhibit a common displacement of 13.8 ± 1.0 nm, corresponding to an effective mean energy correction of 64 ± 11 meV. Independently, the developed interface relation yields 63.44 meV at the nominal emitter–surface separation \(\:d\approx\:4.0\) nm, equivalent to 13.99 nm, using TD-DFT transition moments, dielectric screening, the frequency-dependent Au response, and the structurally constrained emitter–surface separation. This close agreement provides reproducible electrodynamic validation of the observed spectral renormalization. The calculated correction is then transferred, without transition-specific refitting, to a five-transition InP reference hierarchy, producing conditional renormalized predictions while preserving transition ordering. A lifetime consistency check for the conventional 660 nm CdSe–ZnS band gives a calculated quartz lifetime of 19.35 ns, close to the measured value of approximately 20 ns. Combining this calculated lifetime with the experimentally measured quartz-to-Au decay-rate enhancement yields 6.77 ns near Au, consistent with the measured value of approximately 7 ns. The corresponding Au-induced decay-rate factor of 2.86 is subsequently used to predict lifetimes for the four higher-energy transitions.
