Evaluation of a quantitative structure-property relationship (QSPR) for predicting mid-visible refractive index of secondary organic aerosol (SOA).
Evaluation of a quantitative structure-property relationship (QSPR) for predicting mid-visible refractive index of secondary organic aerosol (SOA).
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DOI：
10.1039/c0cp02270e
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发表时间：
2011-03
期刊：
影响因子：
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通讯作者：
Haley E. Redmond;Jonathan E. Thompson
中科院分区：
文献类型：
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作者：
Haley E. Redmond;Jonathan E. Thompson
在这项工作中，我们描述和评估一个简单的方案，通过该方案可以预测的非吸收组分的折射率（λ = 589 nm）的二次有机气溶胶（SOA）共同的分子式和密度（g cm（-3））。所描述的QSPR方法是基于与折射率相关的三个参数-分子极化率、质量密度与分子量的比率和不饱和度。在计算了111种常见于大气气溶胶的化合物的训练集的这些量之后，进行了多元线性回归分析，以建立参数与可接受的折射率值之间的定量关系。当在各种化合物类别中取平均值时，所得的定量关系通常可以将折射率估计为±0.01。一个值得注意的例外是醇类，其模型始终低估了折射率。均匀的内部混合物可以通过使用气溶胶界常用的体积或摩尔分数混合规则来处理。从文献中提出的化学成分数据重建的预测折射率一般同意与以前的SOA折射率的报告。此外，预测的折射率位于我们报告的λ = 532 nm的SOA产生的α-蒎烯（R. I. 1.49-1.51）和甲苯（R.I. 1.49-1.50）。我们设想的QSPR方法可能会发现用于重建光学散射的有机气溶胶，如果质量组成数据是已知的。或者，所描述的方法可以并入有机气溶胶形成/相划分的模型中，以更好地约束有机气溶胶光学性质。
In this work we describe and evaluate a simple scheme by which the refractive index (λ = 589 nm) of non-absorbing components common to secondary organic aerosols (SOA) may be predicted from molecular formula and density (g cm(-3)). The QSPR approach described is based on three parameters linked to refractive index-molecular polarizability, the ratio of mass density to molecular weight, and degree of unsaturation. After computing these quantities for a training set of 111 compounds common to atmospheric aerosols, multi-linear regression analysis was conducted to establish a quantitative relationship between the parameters and accepted value of refractive index. The resulting quantitative relationship can often estimate refractive index to ±0.01 when averaged across a variety of compound classes. A notable exception is for alcohols for which the model consistently underestimates refractive index. Homogenous internal mixtures can conceivably be addressed through use of either the volume or mole fraction mixing rules commonly used in the aerosol community. Predicted refractive indices reconstructed from chemical composition data presented in the literature generally agree with previous reports of SOA refractive index. Additionally, the predicted refractive indices lie near measured values we report for λ = 532 nm for SOA generated from vapors of α-pinene (R.I. 1.49-1.51) and toluene (R.I. 1.49-1.50). We envision the QSPR method may find use in reconstructing optical scattering of organic aerosols if mass composition data is known. Alternatively, the method described could be incorporated into in models of organic aerosol formation/phase partitioning to better constrain organic aerosol optical properties.