Absolute absorption cross sections for two selected lines of formaldehyde around 6625 cm(-1)

作者：Morajkar Pranay; Schoemaecker Coralie; Fittschen Christa^*

来源：Journal of Molecular Spectroscopy, 2012, 281: 18-23.

DOI：10.1016/j.jms.2012.10.004

• CH2O
• Absorption cross sections
• cw-CRDS
• High repetition rate LIF
• Laser photolysis

Absolute absorption cross sections of formaldehyde. CH2O, have been measured at total pressures of 14.5 and 66 mbar Helium by cw-CRDS for two selected lines at around 6625 cm(-1). Absolute CH2O concentrations have been determined in situ by measuring the pseudo-first order decays of OH radicals using high repetition rate laser induced fluorescence (LIF). OH radicals have been generated by laser photolysis of H2O2 in the presence of CH2O and from the well-known rate constant of the reaction of CH2O with OH radicals, the absolute CH2O concentration has been determined. Concentrations between 1.5 and 4 x 10(14) cm(-3) have been used. The line strengths for the lines at 6624.779 cm(-1) and 6625.248 cm(-1) have been found to be (9.1 +/- 1.8) x 10(-24) cm and (5.3 +/- 1.0) x 10(-24) cm, respectively. The broadening coefficients in Helium have also been determined for both lines. Converting the line strengths to absorption cross sections it is found that these values are a factor of 2 smaller than the only known determination of these absorption cross sections in the literature (Staak et al., J. Molec. Spectroscopy 229 (2005) 115-121).

• 出版日期2012-11