Absolute IR band intensities of CH2N2, CH3N3, and CH3NC in the 250-4300 cm(-1) region and upper limits of abundance in Titan's stratosphere

In the frame of a program of systematic studies to determine or reassess the absolute intensities of gas phase organics of interest to Titan, we have experimentally studied the IR spectra in the gas phase of diazomethane, methyl azide, and methyl isocyanide, at room temperature, in the 250-4300 cm(-1) region. The absolute intensities, S-v, of the most intense vibrational bands of these compounds were determined experimentally together with the associated uncertainties. In order to estimate the detectability of the selected compounds by infrared spectroscopy in Titan's atmosphere, our data were compared with Voyager IRIS spectra of Titan. Upper limits of, respectively, 5, 5.4, and 1.3 ppb on the mean stratospheric abundances are inferred. These values are consistent with photochemical modeling of Titan's atmosphere. They appear auspicious for possible detection in Titan using upcoming space missions. (C) 1996 Academic Press, Inc.