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Investigation of ro‐vibrational spectra of small hydrocarbons at elevated temperatures using infrared degenerate four‐wave mixing
Author(s) -
Sahlberg AnnaLena,
Zhou Jianfeng,
Aldén Marcus,
Li Zhongshan
Publication year - 2016
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4862
Subject(s) - hitran , chemistry , spectral line , infrared spectroscopy , analytical chemistry (journal) , infrared , absorption spectroscopy , combustion , spectroscopy , raman spectroscopy , optics , organic chemistry , physics , quantum mechanics , astronomy
The ro‐vibrational spectra around 3 µm of four small hydrocarbons (C 2 H 2 , CH 4 , C 2 H 6 and C 2 H 4 ) at 296, 550 and 820 K have been investigated using infrared degenerate four‐wave mixing (IR‐DFWM). The spectra were recorded in gas flows of nitrogen with small admixtures of the hydrocarbons. A fused silica glass tube surrounded by an electric heating wire was used to heat the gas flows. The recorded IR‐DFWM spectra are compared with simulations using the spectral information available in the HITRAN database, in order to identify spectral lines. The measurements demonstrate good signal to noise ratio and good sensitivity even at elevated temperatures. Several weak hot lines were detected that are not included in the current database. This paper demonstrates the potential of IR‐DFWM for purposes of investigating spectral lines at elevated temperatures, which is often a challenging task with conventional absorption spectroscopy techniques. The possibility of applying IR‐DFWM for combustion diagnostics of small hydrocarbons is discussed from the detection limits of the measurements and the potential water line interference. Because of the non‐linear nature of the DFWM technique, it provides much higher contrast for strong lines of small molecules over backgrounds of high‐density weak lines, which commonly exist in hot gas flows of thermochemical reactions. Copyright © 2016 John Wiley & Sons, Ltd.