%0 Journal Article %1 AK31 %A Pabst, Mathias %A Köhn, Andreas %A Gauss, Jürgen %A Stanton, John F. %D 2010 %J Chem. Phys. Lett. %K chemie imported koehn köhn from:alexanderdenzel theoretische stuttgart theochem %N 1-3 %P 135–140 %R 10.1016/j.cplett.2010.06.023 %T A worrisome failure of the CC2 coupled-cluster method when applied to ozone %U http://dx.doi.org/10.1016/j.cplett.2010.06.023 %V 495 %X The approximate coupled-cluster singles and doubles model CC2 is widely used for calculations of excited states in large molecules. We demonstrate a surprising failure of the CC2 geometry optimization of ozone, whereby the CC2 method predicts a barrierless, exothermic, and symmetric dissociation to three oxygen atoms. This is particularly astonishing since both second-order Møller-Plesset perturbation theory and coupled-cluster singles and doubles give reasonable equilibrium structures. We find that ［［H,T1］,T1］ leads to an unbalanced treatment of T1and T2in the CC2 equations. Results presented here suggest that considerable caution should be exercised when applying the CC2 model to systems with singlet biradical character. © 2010 Elsevier B.V. All rights reserved. %@ 00092614

@article{AK31, abstract = {The approximate coupled-cluster singles and doubles model CC2 is widely used for calculations of excited states in large molecules. We demonstrate a surprising failure of the CC2 geometry optimization of ozone, whereby the CC2 method predicts a barrierless, exothermic, and symmetric dissociation to three oxygen atoms. This is particularly astonishing since both second-order Møller-Plesset perturbation theory and coupled-cluster singles and doubles give reasonable equilibrium structures. We find that ［［H,T1］,T1］ leads to an unbalanced treatment of T1and T2in the CC2 equations. Results presented here suggest that considerable caution should be exercised when applying the CC2 model to systems with singlet biradical character. {\textcopyright} 2010 Elsevier B.V. All rights reserved.}, added-at = {2019-02-06T13:16:27.000+0100}, author = {Pabst, Mathias and K{\"{o}}hn, Andreas and Gauss, J{\"{u}}rgen and Stanton, John F.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2f442c8358eab6921e04935da46a1c9e8/theochem}, doi = {10.1016/j.cplett.2010.06.023}, interhash = {eafef37ccacb9a07584e88ac6b8af462}, intrahash = {f442c8358eab6921e04935da46a1c9e8}, isbn = {00092614}, issn = {00092614}, journal = {Chem. Phys. Lett.}, keywords = {chemie imported koehn köhn from:alexanderdenzel theoretische stuttgart theochem}, number = {1-3}, pages = {135–140}, timestamp = {2019-02-06T12:16:27.000+0100}, title = {{A worrisome failure of the CC2 coupled-cluster method when applied to ozone}}, url = {http://dx.doi.org/10.1016/j.cplett.2010.06.023}, volume = 495, year = 2010 }