PNNL

Abstract

Mukherjee’s and Brillouin-Wigner multi-reference coupled cluster methods were used to study the isomerization of cyclopropane to propene through a trimethylene/propylidene diradicals. Main aim was to obtain high quality ab-initio data using advanced methods that treat both static and dynamic correlation in the involved species. The MkCCSD(T)/cc-pVQZ activation energy of cyclopropane isomerization via trimethylene is 65.6 kcal/mol, in a good agreement with experimental values in the range 60-65 kcal/mol. The MkCCSD(T)/cc-pV5Z adiabatic singlet-triplet gap in trimethylene is 0.6 kcal/mol, slightly higher than previous CASPT2 result -0.7 kcal/mol by Skancke et al.