Recently,AnstÖter and co-workers[J.Am.Chem.Soc.141,6132(2019)]have provided the first photoelectron spectroscopic determination of the anion-πbond strength(De)using iodide-hexafluorobenzene(I-·C6F6)as the a...Recently,AnstÖter and co-workers[J.Am.Chem.Soc.141,6132(2019)]have provided the first photoelectron spectroscopic determination of the anion-πbond strength(De)using iodide-hexafluorobenzene(I-·C6F6)as the archetypical system.In combination with an equation-of-motion coupled cluster theory,namely EOM-IP-CCSD(d T),using Dunning’s aug-cc-p VDZ(a VDZ)basis set,Dein I-·C6F6 was found to be-0.53 e V with an uncertainty less than±0.03 e V.The interaction was claimed to arise for a large part from correlation forces(41%)with only a 23%contribution from electrostatic forces.In the present work,we performed the coupled-cluster with single and double and perturbative triple excitations,CCSD(T),calculations.We found that CCSD(T)/a VDZ can have an uncertainty up to 0.113 e V due to the basis set incompleteness.Our calculations disclosed that the previous calculations on the electrostatic contribution are concealed by the contributions from the exchange and Pauli repulsion.The electrostatic contribution is actually determinant,being more than double of the correlation contribution in the I-·C6F6 complex at the equilibrium binding distance.展开更多
基金supported by the National Natural Science Foundation of China(No.21688102 and No.91027044)。
文摘Recently,AnstÖter and co-workers[J.Am.Chem.Soc.141,6132(2019)]have provided the first photoelectron spectroscopic determination of the anion-πbond strength(De)using iodide-hexafluorobenzene(I-·C6F6)as the archetypical system.In combination with an equation-of-motion coupled cluster theory,namely EOM-IP-CCSD(d T),using Dunning’s aug-cc-p VDZ(a VDZ)basis set,Dein I-·C6F6 was found to be-0.53 e V with an uncertainty less than±0.03 e V.The interaction was claimed to arise for a large part from correlation forces(41%)with only a 23%contribution from electrostatic forces.In the present work,we performed the coupled-cluster with single and double and perturbative triple excitations,CCSD(T),calculations.We found that CCSD(T)/a VDZ can have an uncertainty up to 0.113 e V due to the basis set incompleteness.Our calculations disclosed that the previous calculations on the electrostatic contribution are concealed by the contributions from the exchange and Pauli repulsion.The electrostatic contribution is actually determinant,being more than double of the correlation contribution in the I-·C6F6 complex at the equilibrium binding distance.
