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Fourier transform infrared spectrometer for a single aerosol particle

Sageev Grader, Gideon and Flagan, Richard C. and Seinfeld, John H. and Arnold, Stephen (1987) Fourier transform infrared spectrometer for a single aerosol particle. Review of Scientific Instruments, 58 (4). pp. 584-587. ISSN 0034-6748. http://resolver.caltech.edu/CaltechAUTHORS:SAGrsi87

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Abstract

A spectrometer is reported here for obtaining the infrared spectrum of a single aqueous aerosol particle by a Fourier transform technique. The particle is held in an electrodynamic balance and irradiated simultaneously by the infrared output from a Michelson interferometer and the visible light from a dye laser. The size of the particle is modulated by chopping the IR beam, and the resulting visible scattered light fluctuation is detected at 90° with a photomultiplier tube. The amplitude of the scattered light fluctuation is measured with a lock-in amplifier at each interferometer mirror position. The electronic circuitry for stepping the interferometer mirror is presented and discussed. Inverting the lock-in signal by a discrete fast Fourier transform routine (FFT) yields the particle absorption spectrum. The resulting spectrum for an (NH4)2SO4 droplet is presented.


Item Type:Article
Additional Information:Copyright © 1987 American Institute of Physics. Received 2 December 1986; accepted 18 December 1986. This research was supported by U.S. Environmental Protection Agency Grant R-810857 and by gifts from General Motors Corporation and Mobil Oil Corporation. S. Arnold was supported by a Chevron Visiting Professorship at the California Institute of Technology and by National Science Foundation Grant ATM-8413574. The authors thank Anthony B. Pluchino of the Aerospace Corporation and Ralph Waniak of Advanced Kinetics for helpful advice during this work.
Subject Keywords:FOURIER TRANSFORM SPECTROMETERS, FOURIER TRANSFORM SPECTROSCOPY, AEROSOLS, INFRARED SPECTRA, MICHELSON INTERFEROMETER, LIGHT SCATTERING, DESIGN, OPERATION, ELECTRONIC CIRCUITS, PERFORMANCE, LOCK−, IN AMPLIFIERS, MIRRORS, SIGNAL PROCESSING, AMMONIUM SULFATES, DROPLETS
Record Number:CaltechAUTHORS:SAGrsi87
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:SAGrsi87
Alternative URL:http://dx.doi.org/10.1063/1.1139220
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10138
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:15 Apr 2008
Last Modified:26 Dec 2012 09:57

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