Measurement of Gas and Aerosol Phase Absorption Spectra across the Visible and Near-IR Using Supercontinuum Photoacoustic Spectroscopy

Published

June 22, 2015

Author(s)

James Radney, Christopher Zangmeister

Abstract

We demonstrate a method to measure the absorption spectra of gas and aerosol species across the visible and near-IR (500 to 840 nm) using a photoacoustic (PA) spectrometer and a pulsed supercontinuum laser source. Measurements of gas phase absorption spectra were demonstrated using H2O(g) as a function of relative humidity (RH). The measured absorption intensities and peak shapes were able to be quantified and compared to spectra calculated using the 2012 High Resolution Transmission (HITRAN2012) database. Size and mass selected nigrosin aerosol was used to measure absorption spectra across the visible and near-IR. Spectra were measured as a function of aerosol size/mass and show good agreement to Mie theory calculations. Lastly, we measured the broadband absorption spectrum of flame generated soot aerosol at 5% and 70% RH. For the high RH case, we are able to quantifiably separate the soot and water absorption contributions. For soot, we observe an enhancement in the mass specific absorption cross section ranging from 1.5 at 500 nm (p < 0.01) to 1.2 at 840 nm (p < 0.2) and a concomitant increase in the absorption Ångström exponent from 1.2 +/- 0.4 (5% RH) to 1.6 +/- 0.3 (70% RH).

Citation

Analytical Chemistry

Volume

87

Issue

14

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.analchem.5b01541

Local Download

Keywords

Aerosol absorption spectra, Photoacoustic Spectroscopy

Citation

Radney, J. and Zangmeister, C. (2015), Measurement of Gas and Aerosol Phase Absorption Spectra across the Visible and Near-IR Using Supercontinuum Photoacoustic Spectroscopy, Analytical Chemistry, [online], https://doi.org/10.1021/acs.analchem.5b01541, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918232 (Accessed May 10, 2026)

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