Licht-im-Terrarium: Literaturdatenbank
Licht-im-Terrarium: Literaturdatenbank |
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Flores, M. J., Trainic, M., Borrmann, S., & Rudich, Y. (2009). Effective broadband refractive index retrieval by a white light optical particle counter. Phys. Chem. Chem. Phys. 11(36), 7943–7950. Added by: Sarina (2013-01-23 16:54:54) |
| Resource type: Journal Article DOI: 10.1039/B905292E BibTeX citation key: Flores2009 View all bibliographic details  |
Categories: Englisch = English Keywords: Spektrum = Spectrum Creators: Borrmann, Flores, Rudich, Trainic Collection: Phys. Chem. Chem. Phys. |
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| Abstract |
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A new approach to retrieve the effective broadband refractive indices (nbroad{,}eff) of aerosol particles by a white light aerosol spectrometer (WELAS) optical particle counter (OPC) is presented. Using a tandem differential mobility analyzer (DMA)-OPC system{,} the nbroad{,}eff are obtained for both laboratory and field applications. This method was tested in the laboratory using substances with a wide range of optical properties. With the obtained nbroad{,}eff{,} WELAS aerosol size distributions can be corrected. Therefore{,} this method can be used for instrument calibration in both laboratory and field measurements. The retrieved effective broadband refractive indices for the scattering aerosols were: ammonium sulfate ((NH4)2SO4{,} AS) nbroad{,}eff = 1.52(+/-0.01) + i0.0{,} glutaric acid (HOOC(CH2)3COOH{,} GA) nbroad{,}eff = 1.45(+/-0.01) + i0.0{,} and sodium chloride (NaCl) nbroad{,}eff = 1.49(+/-0.02) + i0.0{,} all within 4% of literature values. A lightly absorbing substance{,} Suwannee river fulvic acid (SRFA){,} was also measured{,} and its retrieved nbroad{,}eff is like that of a pure scatterer{,} with a value of nbroad{,}eff = 1.53(+/-0.01) + i0.0. The retrieved real part of nbroad{,}eff is in accordance with literature values and the imaginary part with the behavior of the white light spectrum of the WELAS{,} which is not sensitive below a wavelength of 380 nm{,} where SRFA mainly absorbs. For absorbing substances{,} nigrosine and various mixtures of nigrosine with AS and GA were measured. For nigrosine{,} nbroad{,}eff = 1.64(+/-0.04) + i0.20(+/-0.03) was retrieved{,} in very good agreement with values found in the literature. The nbroad{,}eff retrieved by this method for the mixtures was in accordance with the complex refractive index expected. The nbroad{,}eff retrieved by this method would be similar to the values obtained using the solar spectrum.
Added by: Sarina |