Vacuum UV Photolysis of Benzene in Solid Nitrogen

The photolysis of C6H6/N-2 matrixsamples at 10 K under 121.6 and 175 nm was investigated, and the observedIR lines were identified by comparison with literature results, expectedphotochemical trends, and isotopic substitution experiments. Under175 nm photolysis, photoproducts were identified, including isomersof benzene, phenyl (Ph) radicals, alkenes and/or alkynes, and purelinear carbon clusters (C-3 and C-5); however,N-bearing hydrocarbons were not detected. In contrast, several newIR signatures were observed upon 121.6 nm photolysis; some of thesesignatures were readily identified as absorptions of CN, HCNC, NC6N, and phenylnitrene (PhN), while the other unknown linesobserved in the typical C VN stretching region were expectedto correspond to linear nitriles. By further warming the sample to30 K, the line intensities of PhN decreased, and the IR lines of anilinoradicals (PhNH) and aniline (PhNH2) were observed, indicativeof the recombination of H atoms with primary photofragments via diffusion.This study provides possible synthetic routes of nitriles and aromaticamines in planetary atmospheres and icy surfaces dominated by N-2.