NEW REFERENCE DATA ON THE THERMODYNAMIC PROPERTIES OF POTASSIUM VAPOR

The functional dependence of the second group integral of temperature is given, which is calculated on the basis of the most recent spectros copic information about interaction potentials of potassium atoms. The degree to which the available experimental data on the density of pot assium vapor agree with one another is analyzed. The experimental data on density were used to derive the semiempirical equation of state fo r potassium vapor in the form of group expansion of density in terms o f degrees of activity. The procedure is proposed for estimating the er ror of calculation of thermodynamic functions based on the derived equ ation of state and results of analysis of experimental data. The calcu lation results are compared with experimental data on heat capacity an d sound velocity in potassium vapors, as well as with calculation data of other authors. Tables are given of the thermodynamic properties of potassium vapor and errors in determining these quantities at tempera tures of 800-2500 K and pressures of 0.01-10 MPa.