Simulating the 3.4-Micron Feature of Titan's Haze

Four prominent features of Titan's haze are found within the '3.4-' absorption to be uniform with recent vertically resolved Cassini/VIMS spectra. These are absorptions at 2998 (3.34 ), 2968 (3.37 ), 2927 (3.42 ), and 2882 (3.47 ). A detailed fitting suggests that the 2998 feature could originate from amorphous acetonitrile () carrying about 25% of integrated optical depth; the remaining features, which account for 75% of the integrated optical depth, could arise from a distinct triplet (C-H stretching) structure of radiolyzed hydrocarbons. An additional feature was possibly evidenced at altitudes higher than 300 km and attributable to 'polymer-capped' methane (), significantly constraining the chemical composition of organic haze layers under Titan's active radiation field.