Spin state splitting in carbon gasification models

Complete active space self-consistent field calculations have been performed on several models commonly used to investigate carbon gasification rates. These calculations clarify the level of electronic spin state splitting in these models. The spin splittings are much smaller than previously calculated, indicating that ab initio methods capable of describing, for example, open shell singlet states are required to perform accurate calculations on these models. The hybrid density functional theory methods commonly used to investigate gasification reactions do not fulfill this criterion.