UV and IR Absorption Cross-sections of HCHO, HCDO, and DCDO

Abstract

UV (240-370 nm) and IR (3200-1500 cm(-1)) absorption cross-sections of HCHO, HCDO, and DCDO in a bath gas of N(2) at atmospheric pressure and 296 K are reported from simultaneous measurements in the two spectral regions. Cross-sections were placed on an absolute scale through quantitative conversion of formaldehyde to CO and HCOOH by titration with Br atoms, also monitored by FTIR. The integrated UV absorption cross-sections of HCHO, HCDO, and DCDO are equal to within the experimental uncertainty.

The HITRAN2012 molecular spectroscopic database

“…In addition, a consistent set of line intensity parameters was generated [222] for both the 5.7-and 3.6-µm spectral regions using high-resolution Fourier transform spectra recorded for the whole 1600 to 3200 cm -1 spectral range. The calculated band intensities derived for the 5.7-and 3.6-µm bands are in excellent agreement with the values achieved recently by medium resolution band intensity measurements [228][229][230]. 33 Details giving the description of the new database which involves 3713 and 31796 transitions at 5.7 and 3.6 µm, respectively, are given in Table 9 of the accompanying paper [222].…”

A simple formulation of the CH<sub>2</sub>O photolysis quantum yields

“…For our calculations of j we will use the absorption spectrum measured by Gratien et al (2007). It is, by the way, Figure 4.…”

“…It is, by the way, Figure 4. Spectra of the actinic photon flux density (WMO, 1985), the optical absorption cross section (Gratien et al, 2007) and mol at 30 km altitude, 33 • solar zenith angle and 227 K. The shaded area represents the integrand σ · · F λ of Eq. (8).…”

“…Given the i from the Eqs. (8) to (10) in Table 1, σ (λ) from Gratien et al (2007) along with vertical temperature and density profiles of the US standard atmosphere (NOAA, 1976) we can calculate the vertical profiles of the photolysis rates. The calculations were made with 1 nm spectral resolution and are shown in Fig.…”

Detection of formaldehyde emissions from an industrial zone in the Yangtze River Delta region of China using a proton transfer reaction ion-drift chemical ionization mass spectrometer

“…HCHO plays a crucial role in atmospheric photochemistry. The absorption spectrum of HCHO extends well into the UVA region and thus its photolysis rate coefficient (Reaction R1) is one of the highest among all carbonyl compounds in the atmosphere (Gratien et al, 2007). Photolysis of HCHO (Reaction R1a) can contribute substantially to the atmospheric HO x radical (OH + HO 2 ) budget and thus can exert great impact on the oxidative capacity of the atmosphere (Volkamer et al, 2010).…”