Electronic and optical properties of flame-generated carbon nanoparticles were modeled based on quantum confinement and amorphous semiconductor theory of monodispersed particles. The ionization energies and optical band gaps of polydispersed particles 4–23 nm in volume median diameter (Liu et al., Proc. Natl. Acad. Sci. U.S.A. 116 (2019) 12692–12697) were re-analyzed by deconvolution to obtain particle-size specific properties. The complex refractive index was derived from optical absorption and the Kramers–Krönig relations over the wavelength range of 185–1400 nm. Dependence of the refractive index on the primary particle size is shown for the first time. The real component of the refractive index is weakly dependent on the particle size, but the imaginary component is found to be particularly sensitive to the particle size. The refractive indices of relatively large soot particles are found to be in close agreement with literature values in the visible spectrum; those of smaller particles (〈 ∼ 15 nm in diameter) show a significant difference from the literature values. The current result highlights the need for accounting for the size effect in the refractive index in laser diagnostics of soot in flames. It also suggests that some of the earlier extinction and scattering measurements of flame soot may have to be re-evaluated, especially for lightly sooting flames and during the early stage of soot growth.

基于量子约束和单分散颗粒的非晶半导体理论，对火焰产生的碳纳米颗粒的电子和光学性质进行了建模。体积中值直径为4-23 nm的多分散颗粒的电离能和光学带隙（Liu等人，Proc。Natl。Acad。Sci。USA通过反卷积对116（2019）12692–12697）进行了重新分析，以获得粒度特定的属性。复折射率是由在185-1400 nm波长范围内的光吸收和Kramers-Krönig关系得出的。首次显示了折射率对一次粒径的依赖性。折射率的实数部分几乎不依赖于粒度，但发现虚数部分对粒度特别敏感。发现较大烟灰颗粒的折射率与可见光谱中的文献值非常吻合。较小颗粒（直径≤15 nm）的那些与文献值显示出显着差异。当前的结果突出显示了在火焰中烟尘的激光诊断中需要考虑折射率的尺寸效应。这也表明可能需要重新评估火焰烟灰的一些早期消光和散射测量值，尤其是对于轻度烟尘火焰以及烟灰生长早期阶段。