Formaldehyde around 3.5 and 5.7-μm: Measurement and calculation of broadening coefficients

Self- and N2-broadening coefficients of H2CO have been retrieved in both the 3.5 and 5.7-μm spectral regions. These coefficients have been measured in FT spectra for transitions with various J (from 0 to 25) and K values (from 0 to 10), showing a clear dependence with both rotational quantum numbers J and K. First, an empirical model is presented to reproduce the rotational dependence of the measured self- and N2-broadening coefficients. Then, calculations of N2-broadening of H2CO were made for some for 3296 ν2 transitions using the semi-classical Robert-Bonamy formalism. These calculations have been done for various temperatures in order to obtain the temperature dependence of the line widths. Finally, self- and N2-broadening coefficients, as well as temperature dependence of the N2-widths has been generated to complete the whole HITRAN 2008 version of formaldehyde (available as supplementary materials).