Light-Induced\nRing-to-Chain Transformations of Elemental\nSulfur: Nonadiabatic Dynamics Simulations

The emergence of high-sulfur content polymeric materials\nand their\ndiverse applications underscore the need for a comprehensive understanding\nof the ring-to-chain transformation of elemental sulfur. In this study,\nwe delve into the ultrafast transformation of the elemental sulfur <b>S</b><sub><b>8</b></sub> ring upon photoexcitation employing\nadvanced nonadiabatic dynamics simulations. Our findings reveal that\nthe bond breaking of the <b>S</b><sub><b>8</b></sub> ring\noccurs within tens of femtoseconds. At the time of bond breaking,\nmost molecules are in the lowest singlet excited state S<sub>1</sub>. S<sub>1</sub> survives for 40–450 fs before relaxing to\nthe quasi-degenerate manifolds formed by the T<sub>1</sub> and S<sub>0</sub> states of the <b>S</b><sub><b>8</b></sub> chain.\nThis suggests that upon photoexcitation the polymerization of the <b>S</b><sub><b>8</b></sub> chains might proceed before the\nchains relax to their lowest energy states. The derived temporal resolution\nprovides a detailed perspective on the dynamics of <b>S</b><sub><b>8</b></sub> rings upon photoexcitation, shedding light on\nthe intricate processes involved in its excited-state transformations.