A Rayleigh mixing rule that relates the effective imaginary part of the refractive index of a composite medium, such as an aerosol or colloid, to the complex refractive index of the Rayleigh particles is derived using Rayleigh scattering theory. The derivation is simple, straightforward, and only weakly dependent on particle morphology. The Rayleigh mixing rule offers an opportunity to derive the imaginary part of refractive index spectra of Rayleigh particles, suspended in a non-absorbing medium with known refractive index spectrum, from an extinction spectrum of the composite medium. However, for this application, the real refractive index spectrum of the particle must be known reasonably well and the imaginary part must be known well enough to decide between two mathematical solutions for it. The Rayleigh mixing rule is compared with widely used mixing rules (i.e., volume, Maxwell Garnett, and Bruggeman mixing rules) and we show that in the small volume fraction regime both the Maxwell Garnet and Bruggeman mixing rules agree with the Rayleigh mixing rule.

中文翻译：

---

Rayleigh 区域中气溶胶或胶体折射率的虚部的混合规则


使用瑞利散射理论推导出了将复合介质（例如气溶胶或胶体）的折射率的有效虚部与瑞利粒子的复折射率相关联的瑞利混合规则。推导简单明了，并且仅微弱地依赖于颗粒形态。瑞利混合规则提供了一个机会，可以从复合介质的消光光谱中推导出悬浮在具有已知折射率光谱的非吸收介质中的瑞利粒子的折射率光谱的虚部。然而，对于此应用，必须对粒子的实际折射率光谱有相当的了解，并且必须对虚部有足够的了解，以便在两个数学解之间做出决定。将 Rayleigh 混合规则与广泛使用的混合规则（即体积、Maxwell Garnett 和 Bruggeman 混合规则）进行比较，我们表明在小体积馏分范围内，Maxwell Garnet 和 Bruggeman 混合规则都与 Rayleigh 混合规则一致。