Interatomic Potential Functions of Sodium and Potassium

Abstract

The liquid structure theory of Born and Green is used to interpret x-ray diffraction measurements on liquid sodium and potassium to find an effective interatomic potential function for pairs of sodium and pairs of potassium atoms. This potential function predicts approximately the correct binding energy for solid sodium and potassium, and when reinserted in the x-ray formulas predicts scattering curves at higher temperatures which are in good agreement with experiments.

Equation of state and manifestation of non-spherical contribution of interaction potential in liquid rubidium metal

“…Since the single valance electrons of the two colliding alkali metal atoms overlap to form a weak chemical bond, it causes the repulsion potential becomes softer than those of normal fluids. On the other hand, alkali metal atoms in liquid state are readily polarized such that the potential function at long range is contributed by more attraction than those of normal fluids [13]. In particular the potential of a light alkali metal has a narrow and deep (hard repulsion) potential well, and a heavy alkali metal has a wide and shallow (soft repulsion) potential well.…”

A new equation of state for molten alkali metal alloys

“…The values of r m calculated from Eq. (10) and those obtained from X-ray diffraction measurements and also literature data [33,34,38] for cesium, potassium, and sodium at their melting temperatures have been given in Table 1. As this table shows, the predicted values are quite close to the literature data.…”

Thermodynamic and Kinetic Properties of Elements and Inorganic Compounds Relating to their Melting and Boiling Point Temperatures

“…The variation of activation energy for viscous flow with the melting point temperature in Figure 16 may be represented by log E v = 1.36 log T m -2.8 (20) where E v is in kJ.…”

“…On the assumption that all liquid metals obey the same interatomic potential energy function and using the experimentally determined values of e/k, d and h for sodium and potassium [20], Chapman evaluated a corresponding state plot of the function h * (V * ) 2 versus T * (Figure 17a). By using this corresponding state relation and assuming that the effective atomic diameter d is the same as that of Goldschmidt's diameter at zero K, Chapman estimated the force constants e/k for several liquid metals from the viscosity data.…”