Realistic foundations for improving the accuracy in refractometry based on an extension of the Lorentz–Lorenz relation

Abstract

Reliable determination of virial coefficients is essential for accurate interpretation of molecular properties, chemical and optical measurements, but their contributions often introduce significant uncertainty when applying the Lorentz–Lorenz relation. In this work, we propose a complementary approach that incorporates molecular dimensions and shape descriptors into the analysis. By studying eight representative molecules, we evaluated their charge-density dimensions and degree of asphericity, from which a new parameter, the shape factor, was defined. This parameter quantifies deviations from ideal behavior and, when applied, reduces the effective influence of virial coefficients by nearly three orders of magnitude. The introduction of the shape factor thus provides a practical tool to minimize systematic errors, enhance measurement precision, and improve the reliability of property estimations derived from the Lorentz–Lorenz equation. Furthermore, this paper presents the validation of an algorithm that facilitates the calculation of refractometric measurements by including the shape factor and molecular species, offering a computational method to streamline data analysis and support experimental design.