Stern-Volmer Fluorescence Quenching

Excited fluorophores in a simulated cuvette either emit a photon after their natural lifetime τ₀ or get silently deactivated when a diffusing quencher molecule collides with them first — the same competition that governs oxygen sensors, protein-folding probes and analyte assays in real fluorescence spectroscopy. This simulator runs that competition as an actual 3D particle system: quencher spheres random-walk through the box, excited fluorophores flash green on emission or fade quietly on a quenching collision, and the live emission rate is used to measure I₀/I and fit the Stern-Volmer constant Ksv in real time, exactly as it would come off a real spectrofluorometer titration.