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Nerf, R.B., Jr., 1975: Pressure broadening and shift in the millimeter-wave spectrum of formaldehyde. J. Molec. Spectrosc., 58, 451-473, doi:10.1016/0022-2852(75)90225-8.
Helium, hydrogen, and self-broadening have been measured at room temperature for 12 lines of formaldehyde between 100 and 300 GHz. The self-broadening parameters ranged from 20 to 30 MHz/Torr, with typical accuracies of 0.5-0.8 MHz/Torr. For all measured lines the helium and hydrogen broadening parameters were 2.5 and 5.5 MHz/Torr, respectively, to within the experimental accuracy, typically 0.25 MHz/Torr. Pressure shifts of up to 2.5 MHz/Torr were observed in self-broadening, with estimated errors of 0.25-0.50 MHz/Torr. No significant lineshifts were seen in the foreign gas broadening measurements.
The observed widths and shifts are compared with those calculated from three models of molecular collisions: Anderson's pressure broadening theory, a similar semiclassical theory of Rabitz and Gordon, and a hard-sphere, sudden approximation model of Thaddeus.
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