TY - JOUR
T1 - A mid-infrared diagnostic for benzene using a tunable difference-frequency-generation laser
AU - Shakfa, Mohammad Khaled
AU - Mhanna, Mhanna
AU - Jin, Hanfeng
AU - Liu, Dapeng
AU - Djebbi, Khalil
AU - Marangoni, Marco
AU - Farooq, Aamir
N1 - KAUST Repository Item: Exported on 2020-10-04
Acknowledgements: Research reported in this publication was funded by the Office of Sponsored Research and King Abdullah University of Science and Technology (KAUST).
PY - 2020/9/16
Y1 - 2020/9/16
N2 - Benzene is a very important molecule in a variety of industrial, environmental, and chemical systems. In combustion, benzene plays an essential role in the formation and growth of polycyclic aromatic hydrocarbons and soot. In this work, a new laser-based diagnostic is presented to make quantitative, interference-free, and sensitive measurements of benzene in the mid-infrared (MIR) region. The diagnostic is based on a widely tunable difference-frequency-generation (DFG) laser system. We developed this laser source to emit in the MIR between 666.54 cm-1 and 790.76 cm-1 as a result of the DFG process between an external-cavity quantum-cascade-laser and a CO2 gas laser in a nonlinear, orientation-patterned GaAs crystal. Benzene measurements were carried out at the peak (673.94 cm-1) of the Q-branch of the v11 vibrational band of benzene. The absorption cross-section of benzene was measured over a range of pressures (4.44 mbar to 1.158 bar) at room temperature. The temperature dependence of the absorption cross-section was studied behind reflected shock waves over 553-1473 K. The diagnostic was demonstrated in a high-temperature reactive experiment of benzene formation from propargyl radicals. The new diagnostic will prove highly beneficial for high-temperature studies of benzene formation and consumption kinetics.
AB - Benzene is a very important molecule in a variety of industrial, environmental, and chemical systems. In combustion, benzene plays an essential role in the formation and growth of polycyclic aromatic hydrocarbons and soot. In this work, a new laser-based diagnostic is presented to make quantitative, interference-free, and sensitive measurements of benzene in the mid-infrared (MIR) region. The diagnostic is based on a widely tunable difference-frequency-generation (DFG) laser system. We developed this laser source to emit in the MIR between 666.54 cm-1 and 790.76 cm-1 as a result of the DFG process between an external-cavity quantum-cascade-laser and a CO2 gas laser in a nonlinear, orientation-patterned GaAs crystal. Benzene measurements were carried out at the peak (673.94 cm-1) of the Q-branch of the v11 vibrational band of benzene. The absorption cross-section of benzene was measured over a range of pressures (4.44 mbar to 1.158 bar) at room temperature. The temperature dependence of the absorption cross-section was studied behind reflected shock waves over 553-1473 K. The diagnostic was demonstrated in a high-temperature reactive experiment of benzene formation from propargyl radicals. The new diagnostic will prove highly beneficial for high-temperature studies of benzene formation and consumption kinetics.
UR - http://hdl.handle.net/10754/665391
UR - https://linkinghub.elsevier.com/retrieve/pii/S1540748920305095
UR - http://www.scopus.com/inward/record.url?scp=85091444563&partnerID=8YFLogxK
U2 - 10.1016/j.proci.2020.06.382
DO - 10.1016/j.proci.2020.06.382
M3 - Article
SN - 1540-7489
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
ER -