Choice of the Ashcroft pseudopotential parameter for the calculation of residual electrical resistivity of dilute binary alloys based on normal metals

The Ashcroft model pseudopotential, which involves only the parameter rc (the radius of an “empty” atomic core), is often used to calculate the value of Δρ/c (the change in the residual electrical resistivity of a metal diluted with 1 at. % impurity). We studied the effect of the parameter rc on (Δρ/c)calc for normal metal-matrices with valence ZM = 1−4 for both the matrix rcM and the impurity rci. Using known data on kF for electrons, we found rcM∗ for 32 elements and the results turned out to be close to the data in the literature. Depending on the position of the element in the periodic table, we observed distinct regularities: rcM∗ increases with the number of the period (for the given group) and increases as the number of the element increases (for the given period). Moreover, the values found for rcM∗ fit perfectly along a straight-line dependence on rs in the form rcM∗=ars+b, where a = 0.48 and b = 0.09 atomic units. The value of a is close to the theoretical value 0.53. The laws previously established (kFrc = 1.00±0.03 and rc = LraZ−1/3, where L = 0.52±0.01 and ra is the atomic radius) are observed with much higher accuracy for the 32 elements. Our studies give reason to hope that the values rc=rcM∗ found can serve as a suitable Aschcroft pseudopotential parameter for the calculation of the residual electrical resistivity of dilute alloys.