Optical characterization of soot (e.g., Laser Induced Incandescence, LII) and its impact on climate largely depend on light absorption. As soot grows, its morphology changes affecting its optical or radiative properties. Here, the impact of soot maturity on its light absorption is investigated by coupling Discrete Element Modeling (DEM) with Discrete Dipole Approximation (DDA) during soot surface growth and agglomeration. The Mass Absorption Cross-section, MAC, of nascent and mature soot agglomerates is estimated by DDA and validated against atomistic point dipole interactions and mesoscale DDA calculations. Using a refractive index, RI, for mature soot yields constant average <MAC> and absorption function <E> overestimating the nascent soot light absorption up to 75%. The RI is interpolated between those of nascent and mature soot for wavelengths, λ = 532 and 1064 nm to account for quantum confinement and evolving number of clustered sp²-bonded rings that affect the optical band gap, E_g. This results in excellent agreement of the DEM-derived evolutions of <MAC> , <E> and ratio R = $\frac{<E(\lambda =532\text{nm})>}{<E(\lambda =1064\text{nm})>}$ with the corresponding LII measurements in methane and ethylene premixed flames. The nascent soot E_g decreases during aging and agglomeration, increasing <MAC> and <E> by 65%. The R decreases from 1.34 to 0.95 by aging and coagulation and slowly converges to the asymptotic 0.89 of mature soot measured in diffusion flames. The good agreement between DEM and LII data confirms that soot dynamics by surface growth and agglomeration strongly correlate with soot maturity, composition and RI that are essential for quantifying soot light absorption and scattering.

烟灰的光学表征（例如激光诱导白炽灯，LII）及其对气候的影响在很大程度上取决于光吸收。随着烟灰的生长，其形态会发生变化，从而影响其光学或辐射特性。在此，通过在烟灰表面生长和团聚过程中将离散元素建模（DEM）与离散偶极近似（DDA）耦合，研究了烟灰成熟度对其光吸收的影响。DDA估算了新生烟灰团块和成熟烟灰团块的质量吸收截面MAC，并针对原子点偶极子相互作用和中尺度DDA计算进行了验证。使用折射率RI可获得成熟的烟ot，得出恒定平均值< MA C>和吸收函数< E>高估了初生烟灰吸收率高达75％。所述RI是那些初生之间内插和成熟为烟灰的波长，λ  = 532和1064 nm至帐户量子约束和群集SP的不断发展的数²影响光学带隙，键合的环ë_克。这导致DEM派生的< MAC >，< E >和比率R  =的 一致性极好。$\frac{<E（\lambda =532\text{纳米}）>}{<E（\lambda =1064\text{纳米}）>}$并在甲烷和乙烯预混火焰中进行相应的LII测量。初生烟灰E _g在老化和结块过程中降低，使< MA C>和< E >增加65％。所述ř由老化和凝结从1.34下降到0.95，慢慢收敛到在扩散火焰测量成熟的烟灰的渐近0.89。DEM和LII数据之间的良好一致性证实，通过表面生长和团聚产生的烟尘动力学与烟尘的成熟度，组成和RI密切相关，而烟尘的成熟度，组成和RI是量化烟尘光吸收和散射所必不可少的。