Automerization reaction of cyclobutadiene and its barrier height: an ab initio benchmark multireference average-quadratic coupled cluster study.

@article{EckertMaksi2006AutomerizationRO,
  title={Automerization reaction of cyclobutadiene and its barrier height: an ab initio benchmark multireference average-quadratic coupled cluster study.},
  author={Mirjana Eckert-Maksi{\'c} and Mario Vazdar and Mario Barbatti and Hans Lischka and Zvonimir B. Maksi{\'c}},
  journal={The Journal of chemical physics},
  year={2006},
  volume={125 6},
  pages={64310}
}
The problem of the double bond flipping interconversion of the two equivalent ground state structures of cyclobutadiene (CBD) is addressed at the multireference average-quadratic coupled cluster level of theory, which is capable of optimizing the structural parameters of the ground, transition, and excited states on an equal footing. The barrier height involving both the electronic and zero-point vibrational energy contributions is 6.3 kcal mol(-1), which is higher than the best earlier… CONTINUE READING