Fractionnement isotopique lors des changements d‘état solide-vapeur et liquide-vapeur de l'eau à des températures inférieures à 0°C

Abstract

Measurements of the hydrogen isotopic composition of water in atmospheric precipitations make possible the study of their formation and evolution, since deuterium is a natural tracer for the water molecule. In a hydrologic cycle, each change of state is accompanied by an isotopic fractionation expressed in terms of a factor ?, which is a function of temperature. This fractionation is due to differences in the physical properties of the molecules H₂O and HDO. In the work described in this paper we have measured ? between ?40°C and 0°C for the phase equilibrium ice-water vapor and between ?15°C and 0°C for the equilibrium liquid-water vapor. The values obtained may be expressed in the relations log ?solide-vapeur= ?4.10 · 10^?2 + 7.074/T² log ?liquide-vapeur= ? 4.34 · 10^?2 + 6.520/T². DOI: 10.1111/j.2153-3490.1967.tb01465.x