High-information time-resolved Fourier transform spectroscopy at work.

The first instrumental setup, to our knowledge, that is capable of recording in a few hours the time-resolved Fourier transform (TRFT) interferograms of gas-phase spectra that cover several thousands of inverse centimeters with spectral- and time-resolution limits that are equal, at best, to 2.5 x 10(-3) cm(-1) and 2 ns, respectively, is reported. It was developed on the stepping-mode Connes-type interferometer of the Laboratoire de Photophysique Moléculaire Université de Paris Sud. Also, for the first time, to our knowledge, these high-resolution TRFT spectra, illustrated with the Doppler-limited emission spectra of the N(2) transitions (B-A) and (B'-B) between 5500 and 11 000 cm(-1) and of the atomic Ar lines between 1800 and 4000 cm(-1), are recorded in the infrared spectral range. To obtain identical results that have the same signal-to-noise ratio, we should have increased the recording time of our unique previous high-information TRFT spectra by approximately 50,000. In other words, one hour is now long enough to obtain what would previously have required six years to record.