Abstract

A finite element analysis method for numerical modeling of the photothermal deflection spectroscopy of aerosols is presented. The models simulate pulse-laser excited photothermal deflection from aerosols collected on a plane surface substrate in air medium. The influence of the aerosol and substrate properties on the transient photothermal deflection signal is examined. We have previously obtained experimental results for photothermal deflection spectrometry of aerosols deposited onto a plate from an impactor system (O. O. Dada and S. E. Bialkowski, Appl. Spectrosc. 62, 1336 (2008)). This paper supports the validity of the experimental results presented in that paper and helps in answering some of the questions raised. The modeling results presented here demonstrate that the (peak) normalized transient temperature change profile and (peak) normalized transient photothermal deflection profile are a good approximation and invariant with number of particles, inter-particle distance, and particulate shape, which suggests that the photothermal deflection signal amplitude may be calibrated linearly with total mass of aerosols and the method could be applied to analysis of complex aerosols.

Accounting for absorption saturation effects in pulsed infrared laser-excited photothermal spectroscopy

Stephen E. Bialkowski
Appl. Opt. 32(18) 3177-3189 (1993)

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Appl. Opt. 24(3) 422-433 (1985)

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Jianqin Zhou, Jianhua Zhao, Jun Shen, and Mauro Luciano Baesso
J. Opt. Soc. Am. B 22(11) 2409-2416 (2005)

Time-resolved, photothermal-deflection spectrometry with step optical excitation

Jianhua Zhao, Jun Shen, Cheng Hu, Jianqin Zhou, and Mauro Luciano Baesso
J. Opt. Soc. Am. B 21(5) 1065-1072 (2004)

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Mireille Commandré and Pierre Roche
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