Infrared spectroscopy of crystalline and amorphous diacetylene (C4H2) and implications for Titan’s atmospheric composition

New laboratory spectra of crystalline and amorphous diacetylene ice have been recorded in the range of 7000–500 cm (1.4–20mm) to aid in the identification of solid diacetylene on Saturn’s moon Titan. We have established that amorphous diacetylene ice is stable only at temperatures less than 7071K. With respect to observations on Titan, the best approach would be to utilize future space-based telescopes to search for the n4 (3277/3271 cm ) in absorption against the reflected light from the sun and the slightly weaker n8 absorption bands (676/661 cm ) in absorption against the continuum emission. & 2009 Elsevier Ltd. All rights reserved.