A transformed framework for dynamic correlation in multireference problems
We describe how multireference dynamic correlation theories can be naturally obtained as single-reference correlation theories in a canonically transformed frame. Such canonically transformed correlation theories are very simple and involve identical expressions to their single-reference counterparts. The corresponding excitations involve quasiparticles rather than the bare particles of the system. High-order density matrices (or their approximations) and the numerical metric instabilities common to multireference correlation theories do not appear. As an example, we formulate the Bogoliubov canonically transformed version of second-order Møller-Plesset perturbation theory and demonstrate its performance in H₂, H₂O, N₂, and BeH₂ bond dissociation.
© 2015 AIP Publishing LLC. Received 31 October 2014; accepted 16 March 2015; published online 30 March 2015. This work was supported by the US Department of Energy, Office of Science through Award Nos. DE-SC0008624 and DE-SC0010530. The authors would like to thank Bo-Xiao Zheng and Francesco Evangelista for helpful discussions.
In Figs. 1–4 of our recent paper,1 the reference CASPT2 potential energy curves did not include contributions from single excitations (i → x, i → a, and x → a). This was not stated in our manuscript. The conclusions of our paper are not affected.
Published - 1_2E4916315.pdf
Erratum - 1_2E4941607.pdf
Accepted Version - 1411.0067.pdf