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RESEARCH PRODUCT
Communication: The pole structure of the dynamical polarizability tensor in equation-of-motion coupled-cluster theory.
Jürgen GaussAnna I. KrylovKaushik D. Nandasubject
Physics010304 chemical physicsAmplitude responseStructure (category theory)General Physics and AstronomyEquations of motionState (functional analysis)Physics::Classical Physics010402 general chemistryPolarizability tensor01 natural sciences0104 chemical sciencesCoupled clusterClassical mechanicsScheme (mathematics)0103 physical sciencesPhysical and Theoretical Chemistrydescription
In this letter, we investigate the pole structure of dynamical polarizabilities computed within the equation-of-motion coupled-cluster (EOM-CC) theory. We show, both theoretically and numerically, that approximate EOM-CC schemes such as, for example, the EOM-CC singles and doubles model exhibit an incorrect pole structure in which the poles that reflect the excitations from the target state (i.e., the EOM-CC state) are supplemented by artificial poles due to excitations from the CC reference state. These artificial poles can be avoided by skipping the amplitude response and reverting to a sum-over-states formulation. While numerical results are generally in favor of such a solution, its major drawback is that this scheme violates size extensivity.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-10-15 | The Journal of chemical physics |