FTS generalized apparatus function

A general analytical expression is proposed for the apparatus function of any Fourier transform spectrometer, which takes into account the throughput, a possible slight asymmetry of the line profiles due to a residual phase error, as also a chromatic variation of the radiant energy received by the detectors during the recording of the interferogram. An experimental example is used to exhibit the large errors appearing in the retrieved line intensities and collisional widths when one analyzes the observed line profiles with the classical apparatus function, instead of the generalized expression given in this paper. (C) 1998 Elsevier Science Ltd. All rights reserved.