Beyond Beer's Law: Why the Index of Refraction Depends (Almost) Linearly on Concentration.

ABSTRACT: Beer's empiric law states that absorbance is linearly proportional to the concentration. Based on electromagnetic theory, an approximately linear dependence can only be confirmed for comparably weak oscillators. For stronger oscillators the proportionality constant, the molar attenuation coefficient, is modulated by the inverse index of refraction, which is itself a function of concentration. For comparably weak oscillators, the index of refraction function depends, like absorbance, linearly on concentration. For stronger oscillators, this linearity is lost, except at wavenumbers considerably lower than the oscillator position. In these transparency regions, linearity between the change of the index of refraction and concentration is preserved to a high degree. This can be shown with help

SUBMITTER: Mayerhofer TG 

PROVIDER: S-EPMC7216834 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature