EN
Assuming that V(x) ≈ (1 - μ) G_1(x) + μ L_1(x) is a very good approximation of the Voigt function, in this work we analytically find μ from mathematical properties of V(x). G_1(x) and L_1(x) represent a Gaussian and a Lorentzian function, respectively, with the same height and HWHM as V(x), the Voigt function, x being the distance from the function center. In this paper we extend the analysis that we have done in a previous paper, where μ is only a function of a; a being the ratio of the Lorentz width to the Gaussian width. Using one of the differential equation that V(x) satisfies, in the present paper we obtain μ as a function, not only of a, but also of x. Kielkopf first proposed μ (a, x) based on numerical arguments. We find that the Voigt function calculated with the expression μ (a, x) we have obtained in this paper, deviates from the exact value less than μ(a) does, specially for high |x| values.