Theoretical calculations peroxide group

For more than forty years the Bartlett butterfly TS was the generally accepted mechanism for peracid epoxidation and numerous experimental studies supported this transition structure" " . During these formative years theoretical calculations did not play a major role due to limitations of available methods that could adequately treat the peroxide functional group. Theoretical contributions in 1978 were at the Hartree-Fock (HF) level since... 

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