Foreign gas broadening of an IR absorption line of formaldehyde

An enclosive flow cooling (EFC) cell has been constructed, and coupled to a Brüker IFS 120HR high resolution Fourier transform spectrometer to record rotationally cold absorption spectra of gases of atmospheric interest at high spectral resolution. The new system has been characterized using N2O, revealing that rotational temperatures as cold as 110 K are readily attainable using liquid nitrogen as a cryogen. Infrared spectra of the (nu)4 band of 1,1-difluoroethane (R152a), C(H)3CH(F)2, cooled in the EFC cell have been measured at a resolution of 0.0019 cm-1. Eight hundred and twenty rovibrational transitions of the weak (nu)4 band with 2