The theory of the entropy and enthalpy of solution of chemical impurities

Abstract

Calculations of the entropy and enthalpy of solution of H, C, N and O in liquid sodium and of hydrogen isotopes in liquid lithium are presented. The results are based on the methods described in Mainwood and Stoneham (1978), paper I, combined with electronic-structure calculations for the solvation cluster. The cluster calculations use an approximate molecular orbital method (CNDO) parameterized independently, from molecular data. In most cases the predictions agree well with experiment. Since there are large cancellations between the various calculated and tabulated contributions to the entropy and enthalpy, this success confirms that we have developed a practical and sufficiently accurate approach to some of the difficult problems of chemical impurities in metals.