Thermodynamic study of the vaporization of europium sulfide by the mass spectrometric Knudsen cell method

The evaporation of europium sulfide was studied in the temperature interval 1550 to 2480 K by the mass spectrometric Knudsen cell technique. A figure summarizes the variation with reciprocal temperature of the logarithm of the pressures corresponding to congruent effusion, and the comparison with the literature data. The atomization enthalpies of the condensed phase and of the gaseous species were determined by the second and third laws. The results are summarized. The thermodynamic function used in the calculations are given, and the molecular parameters on which they are based. (U.K.)