Propagation of a free electron laser beam of wavelength 4mm through sulphar dioxide is studied. The frequency interval considered is from 2523.336 to 2524.727 cm-1. Values of transmittance, averaged over intervals of 0.1 cm-1, are calculated for absorber thickness 0.01, 0.1 and 1 atmcm by the help of quasi random model of molecular band absorption. From generated absorptance values intensities of the high resolution absorption lines in the above interval of SO2 can be simulated. There is a scope to apply this work in atmospheric optics.
