PHOTOPOLYMERIZATION AND MASS-INDEPENDENT SULFUR ISOTOPE FRACTIONATIONS IN CARBON-DISULFIDE

Irradiation of gaseous carbon disulfide [CS2(g)] at 313 nanometers pro duces a dark brown aerosol of (CS2)(x). Its thermal decomposition prod ucts include disulfur (S-2), carbon monosulfide (CS), and (CS)(x). The photopolymerization process is accompanied by a large mass-independen t isotopic fractionation of sulfur (a 5 to 10 per mil sulfur-33 excess and a 61 to 84 per mil sulfur-36 deficit). Excess sulfur-33 has been observed in several classes of meteorites, Photochemical production of (CS2)(x) may be important in the origin and evolution of cosmochemica l environments such as the presolar nebula, meteorites, asteroids, and planetary atmospheres.