For small changes such as occur during transport of water vapour through the atmosphere, the differentiated equation will usually be sufficient. distillation of heavy water, these formulae need to be integrated over the distillation trajectory. R R 0 = ( X X 0 ) a − 1 įor large changes in concentration, such as they occur during e.g. Under these conditions, the evolution of the isotopic composition in the residual (reactant) material is described by: The equations can be used to describe an isotope fractionation process if: (1) material is continuously removed from a mixed system containing molecules of two or more isotopic species (e.g., water with 18O and 16O, or sulfate with 34S and 32S), (2) the fractionation accompanying the removal process at any instance is described by the fractionation factor a, and (3) a does not change during the process. This is an exponential relation that describes the partitioning of isotopes between two reservoirs as one reservoir decreases in size. The original Rayleigh equation was derived by Lord Rayleigh for the case of fractional distillation of mixed liquids. Distillation (Rayleigh) Francis Albarede Reference work entry 110 Accesses Definition This term applies to chemical and isotopic fractionation during phase transformation when one phase progressively evolves from another of limited size and is continuously removed. Rayleigh fractionation holds particular importance in hydrology and meteorology as a model for the isotopic differentiation of meteoric water due to condensation. It is used in particular to describe isotopic enrichment or depletion as material moves between reservoirs in an equilibrium process. Rayleigh fractionation describes the evolution of a system with multiple phases in which one phase is continuously removed from the system through fractional distillation. Please help improve this article by introducing citations to additional sources.įind sources: "Rayleigh fractionation" – news Relevant discussion may be found on the talk page. This article relies largely or entirely on a single source.
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