Tầm quan trọng của hạt aerosol trong nhiều ngành khoa học, chẳng hạn như hóa học khí quyển, đốt, interfacial khoa học, và chế biến vật liệu, đã được ổn định phát triển trong quá khứ thập kỷ qua. Một trong những tính chất độc đáo của các hạt này là bề mặt khối lượng tỷ lệ rất cao, do đó làm cho chúng sẵn sàng phục vụ như trung tâm cho giai đoạn ngưng tụ khí và các phản ứng không đồng nhất. Những hạt này phải được đặc trưng bởi hình dạng, kích thước, trạng thái vật lý, và thành phần hóa. | 8 Chemical Characterization of Aerosol Particles by Laser Raman Spectroscopy K. Hang Fung and Ignatius N. Tang CONTENTS Experimental Laser Sample Generation and Collection Optics Spectrometers and Current Advances in Chemical Analyses of Aerosol Characterization and Quantitative Resonance Raman Future Development and INTRODUCTION The importance of aerosol particles in many branches of science such as atmospheric chemistry combustion interfacial science and material processing has been steadily growing during the past decades. One of the unique properties of these particles is the very high surface-to-volume ratios thus making them readily serve as centers for gas-phase condensation and heterogeneous reactions. These particles must be characterized by size shape physical state and chemical composition. Traditionally optical elastic scattering has been applied to obtain the physical properties of these particle . particle size size distribution and particle density . These physical properties are particularly important in atmospheric science as they govern the distribution and transport of atmospheric aerosols. The chemical characterization of airborne particles has always been tedious and difficult. It involves many steps in the process namely sample collection species and or size separation and chemical analysis. There is a great need for non-invasive methods for in situ chemical analysis of suspended single particles. For bulk samples Raman scattering fluorescence emission and infrared absorption are the most common spectroscopic techniques. While fluorescence spectroscopy is extremely sensitive in terms of detection limit 1 it lacks the spectral specificity required for chemical This research was performed under the auspices of the . Department of Energy under Contract No. DE-AC02-76CH00016. 177
