Vacuum ultraviolet photoabsorption spectra of nitrile ices for their identification on Pluto

Icy bodies, such as Pluto, are known to harbor simple and complex molecules. The recent New Horizons flyby of Pluto has revealed a complex surface composed of bright and dark ice surfaces, indicating a rich chemistry based on nitrogen (N 2 ), methane (CH 4 ), and carbon monoxide (CO). Nitrile (CN) containing molecules such as acetonitrile (CH 3 CN), propionitrile (CH 3 CH 2 CN), butyronitrile (CH 3 CH 2 CH 2 CN), and isobutyronitrile ((CH 3 ) 2 CHCN) are some of the nitrile molecules that are known to be synthesized by radiative processing of such simple ices. Through the provision of a spectral atlas for such compounds we propose that such nitriles may be identified from the ALICE payload on board New Horizons