Förster cycle

An indirect method of determination of excited state equilibria, such as p K *,a values, based on ground state thermodynamics and electronic transition energies. This cycle considers only the difference in molar enthalpy change (Δ Δ H) of reaction of ground and excited states, neglecting the difference in molar entropy change of reaction of those states (Δ Δ S).
Source:
PAC, 1996, 68, 2223 (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2243