Alfred Klemm

Fractionation of Oxygen Isotopes at the Faces of Smoky Quartz

Abstract The 18O /16O ratio under the m- and r-faces of smoky quartz has been measured; the ratio of the growth velocities was Vm/Vr = 1/3. The obtained separation factor 1.00020 is compared with that obtained previously for amethyst (1.00043), where the ratio Vm/Vr was unity

A New Intracrystalline Isotope Effect: 18O under the Faces of Amethyst

Abstract The concentration of 18O within well formed crystals of amethyst was found to vary beneath the different growth faces, increasing in the order z→ r→m. The 18O/16O fractionation factor between the faces m and z was measured as 1.0007.

Further Study of Intersectorial Isotope Fractionation in Quartz

Abstract It is shown that the intersectorial boundary in crystals must be straight if the intersectorial isotope effect is to be measured in the presence of isotopical mantle zoning.

Zonar Distribution of 18O in Synthetic Quartz Crystals

Abstract The 18O-content in the mantle-zones of a commercial synthetic quartz was found to increase from the seed towards the surface by 7 ‰. Since the growth took place in a closed container, calculations for the evolution towards the steady state of the 18O-transport could be performed. In the steady state the concentrations of 18O and impurities in the growing quartz are uniform.

ASSOCIATION IN MOLTEN SALTS AND MOBILITY ISOTHERMS SHOWING THE CHEMLA EFFECT

Abstract In 1984 a model for additive binary molten salt mixtures had been proposed that allowed for a qualitative understanding of the occurence of the Chemla effect (equal internal mobilities at a certain mixing ratio of the salts). In that model the presence of three ions (1,2 and 3) and two neutral molecules (4 and 5) consisting of two ions is assumed, and the ratios K1 = x4 / x1x3 and K2 = X5 / X2X3 of their mole fractions are assumed to be independent of the mixing ratio of the salts. In the present paper, that model is compared with recent experimental results on the system (Li, Cs)Cl obtained in Japan. The comparison shows that the model is too simple for a quantitative description of systems showing the Chemla effect. Rather a dependence of K1 and K2 on the mixing ratio of the salts must be assumed.

Die Sonne, der Obelisk und die Ara Pacis Augustae/ The Sun, the Obelisk, and the Ara Pacis Augustae

From the fact that Rome lies at 41.9° northern latitude, the distance of the ara pacis Augustae from the obelisk was 85 m, the length of the obelisk is 30m and its shadow did not reach the ara during the summer half and reached it, provided the sun did shine, daily during the winter half it is concluded that the ara was situated 18.45° north of the west-east axis, and the shadow reached the ara at 16 o’clock and 24 minutes central European winter time.

Further measurements of the zonar distribution of 18O in synthetic quartz crystals

Abstract The isotop effect δ18OF -δ18Os, measured between the face F and the solvent S of synthetic quartz crystals, grown at 1 kbar and 550-700 K, has been estimated to be 5.4, 18O being enriched in the solid.

Coion-Interactions in Molten Salt Systems (M1 ,M2 )X3

Abstract The association-model of binary molten salt systems (M1,M2)X3 is critizised and the friction coefficients r1,3, and r23 of the system (6Li, 7Li)Cl are calculated from ancient mobility mea-surements, showing that the coion-interactions, represented by r12, are about as strong as the ion-counterion-interactions, represented by r13 and r23.

Theory of linear response applied to the lithium isotope effects on the mobilities in molten LiCl

Abstract Expressions in terms of group-velocity time-correlation functions for the ionic mobilities of molten 6LiCl,7 LiCl and (6Li,7 Li)Cl are derived, taking the time-averaged zero momentum of inertia of each of the three groups of ions into account. MD-simulations have been performed for 6LiCl and 7LiCl, yielding agreement between the simulated and the published experimental reduced isotope effect, although the temperature -volume conditions of the simulations did not conform with natural LiCl.