Firanescu George, Signorell Ruth
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
J Phys Chem B. 2009 May 7;113(18):6366-77. doi: 10.1021/jp8101767.
The influence of shape, size, and internal structure of CO aerosol particles on mid-infrared spectra is modeled for aggregates in the size range between 1 and 100 nm. Combining the vibrational exciton model with a molecular dynamics approach, we identify spectral features that are characteristic for the shape of the particles and for their internal structure (crystalline, amorphous, and partially amorphous) over the whole particle size range. The characteristic size-dependent patterns in the spectra of small particles (<10 nm) are lost for particle ensembles with typical size distributions. The comparison with calculated infrared spectra allows us to analyze experimental spectra of large particles (10-100 nm). Furthermore, we extract refractive index data for crystalline, amorphous, and partially amorphous CO ices from calculated infrared particle spectra.
针对尺寸在1至100纳米范围内的团聚体，模拟了一氧化碳气溶胶颗粒的形状、大小和内部结构对中红外光谱的影响。将振动激子模型与分子动力学方法相结合，我们确定了在整个颗粒尺寸范围内，颗粒形状及其内部结构（晶体、非晶体和部分非晶体）所特有的光谱特征。对于具有典型尺寸分布的颗粒集合体，小颗粒（<10纳米）光谱中与尺寸相关的特征模式消失了。与计算得到的红外光谱进行比较，使我们能够分析大颗粒（10 - 100纳米）的实验光谱。此外，我们从计算得到的红外颗粒光谱中提取了晶体、非晶体和部分非晶体一氧化碳冰的折射率数据。
