Importance of Intersystem Crossing on Flammability Properties of Carbon Disulphide (CS2)
Carbon disulphide (CS2) represents an important chemical commodity, unfortunately, found responsible for several factory, laboratory and transportation fires. This contribution examines the high flammability of CS2 by exploring the fire chemistry of the intersystem crossing (ISC) process that occurs within the two key elementary reactions. By expanding the potential enthalpy surfaces of CS + O2 reaction into three-dimensional space, we reveal the unusual changeover from the triplet surface onto the singlet surface through the ISC point. We calculate the minimum energy crossing point to locate the ISC structure, resulting in a lowered activation energy for the CS2 + O2 and CS + O2 reactions. This enables us to explain the low ignition temperature and high flammability of CS2, a common compound in the chemical industry.
KeywordsFlammability Potential enthalpy surface (PES) Intersystem crossing (ISC) Minimum energy crossing point (MECP)
This study has been supported by funds from the Australian Research Council (ARC), and grants of computing time from the National Computational Infrastructure (NCI) Australia and the Pawsey Computing Centre in Perth. Zhe Zeng thanks Murdoch University for postgraduate research scholarships.
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