Calculates the Wigner-Seitz radius discontinuity contribution to the gamma factor in the Miedema model of mixing enthalpy. See equation 1 of: http://dx.doi.org/10.1016/j.cpc.2016.08.013

Parameters:¶

element_a: str¶

The periodic table symbol of element A

element_b: str¶

The periodic table symbol of element B

Q: Number¶

An empirical factor dependent on the kinds of elements being mixed. Dependent on the P factor discussed, Q = 9.4*P, discussed in documentation of calculate_electronegativity_enthalpy_component().