Time-resolved wavelength modulation spectroscopy measurements of HO{sub 2} kinetics
High-frequency wavelength modulation spectroscopy (WMS) has been applied to the detection of the hydroperoxyl radical (HO{sub 2}) in a laser photolysis and long-path absorption pump-probe kinetics reactor with a near-infrared distributed feedback diode laser. The HO{sub 2} is formed by the 355-nm photolysis of Cl{sub 2} in the presence of CH{sub 3}OH and O{sub 2} and monitored by a phase-sensitive detection of the second-harmonic (2f) signal in the 2{nu}{sub 1} band with a 1.5-{mu}m diode laser directly modulated at 5 MHz. The measured 2f WMS signal is calibrated by direct absorption and converted to an absolute number density with the known absorption line strength of the HO{sub 2} line at 6625.80 cm{sup {minus}1}. The utility of time-resolved WMS as a second-order kinetics probe is demonstrated through the measurement of the HO{sub 2} self-reaction rate constant at 295 K. {copyright} 1997 Optical Society of America
- OSTI ID:
- 365346
- Journal Information:
- Applied Optics, Journal Name: Applied Optics Journal Issue: 24 Vol. 36; ISSN APOPAI; ISSN 0003-6935
- Country of Publication:
- United States
- Language:
- English
Similar Records
Measurements of line strengths in the HO sub 2. nu. sub 1 overtone band at 1. 5. mu. m using an InGaAsP laser
Method for calibration-free scanned-wavelength modulation spectroscopy for gas sensing