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Showing 1 to 6 of 6 for “"size-consistency"”.
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Accelerating vibrational free energy calculations for anharmonic crystals
… focus on exploiting the notions of symmetry and size consistency to reduce the computational cost of the method and to improve its accuracy and reliability. The discussions of symmetry and size consistency also reveal a number of fundamental problems with the VSCF method. Solutions are proposed …
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Describing Charge Transfer in Extended Donor-Acceptor Systems with Density Functional Theory
… of GKS theory. We consider DA systems of various sizes that are composed of thiophene as donor and benzothiadiazole or naphthalene diimide as acceptor. We show how the optical and electronic properties can be tailored by changing the conjugation length and the arrangement of the donor and acceptor …
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Electron Correlation Studies of Weakly Bonded Systems
… and CCD curves are similar suggesting that the size-consistency error is of minor importance. The CEPA-0 potential curves of the Be dimers have deep, close-in wells while the SCEP and CCD potential curves have shallower wells. SCEP and CEPA-2 calculations are also reported for Mg(,4). The Mg(,4) …
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Diagrammatic theories for the vibrational many-body problem
… potential energy surface (PES). Diagrammatically size-consistent and basis-set-free vibrational coupled-cluster (XVCC) theory for both zero-point energies and transition frequencies, the latter through the equation-of-motion (EOM) formalism, is defined for an $n$th-order Taylor-series PES. …
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Diagrammatic many-body methods for anharmonic molecular vibrational properties
… XVSCF and XVMP2 methods are guaranteed to be size-consistent at the formalism level, meaning that they are applicable not only to small molecules but also to larger systems including condensed phases. The XVSCF method, initially developed by Keçeli and Hirata, is extended to calculate …
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Vibrational many-body methods for molecules and extended systems
… in the formalisms of VSCF that have nonphysical size dependence, leading to compact and strictly size-extensive equations. This size-extensive VSCF method (XVSCF) thus defined has no contributions from cubic force constants and alters only the transition energies of the underlying …