Complex absorbing potentials within EOM-CC family of methods: Theory, implementation, and benchmarks

Zuev, Dmitry; Jagau, Thomas-C.; Bravaya, Ksenia B.; Epifanovsky, Evgeny; Shao, Yihan; Sundstrom, Eric J.; Head‐Gordon, Martin; Krylov, Anna I.

doi:10.1063/1.4885056

Cited by 136 publications

(244 citation statements)

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“…First of all, we note that the cc-pVTZ + (2p2s1d) value is practically identical to the class (3) absorbing potential equation-of-motion result reported in Ref. 28, which was obtained with the same valence basis set, reemphasizing the reliability of the ACCC method. Regarding different valence basis sets, the trend for the 2 Π u resonance of CO − 2 is similar to the trend observed for FIG.…”

Section: B Moleculessupporting

confidence: 84%

“…The standard correlation-consistent basis sets have been augmented with a (2s2p1d) set, respectively, and all results have been obtained with a soft Voronoi-box stabilizing potential. For each basis set, the Padé [2,2], [3,3], and [4,4] the lowest π * resonance of CH 2 O − , CO − , and C 2 H − 4 : 27,28 The real parts converge fairly quickly-at least to the extent that the continuum method itself is introducing uncertainties-and convergence is typically from above, as there is more electron correlation in an open-shell (N + 1) electron system than in its closed-shell N electron parent. The lifetime, however, shows more relative variation and no systematic convergence.…”

Section: B Moleculesmentioning

confidence: 99%

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Short-range stabilizing potential for computing energies and lifetimes of temporary anions with extrapolation methods

Sommerfeld

Ehara

2015

The Journal of Chemical Physics

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The energy of a temporary anion can be computed by adding a stabilizing potential to the molecular Hamiltonian, increasing the stabilization until the temporary state is turned into a bound state, and then further increasing the stabilization until enough bound state energies have been collected so that these can be extrapolated back to vanishing stabilization. The lifetime can be obtained from the same data, but only if the extrapolation is done through analytic continuation of the momentum as a function of the square root of a shifted stabilizing parameter. This method is known as analytic continuation of the coupling constant, and it requires--at least in principle--that the bound-state input data are computed with a short-range stabilizing potential. In the context of molecules and ab initio packages, long-range Coulomb stabilizing potentials are, however, far more convenient and have been used in the past with some success, although the error introduced by the long-rang nature of the stabilizing potential remains unknown. Here, we introduce a soft-Voronoi box potential that can serve as a short-range stabilizing potential. The difference between a Coulomb and the new stabilization is analyzed in detail for a one-dimensional model system as well as for the (2)Πu resonance of CO2(-), and in both cases, the extrapolation results are compared to independently computed resonance parameters, from complex scaling for the model, and from complex absorbing potential calculations for CO2(-). It is important to emphasize that for both the model and for CO2(-), all three sets of results have, respectively, been obtained with the same electronic structure method and basis set so that the theoretical description of the continuum can be directly compared. The new soft-Voronoi-box-based extrapolation is then used to study the influence of the size of diffuse and the valence basis sets on the computed resonance parameters.

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Section: B Moleculessupporting

confidence: 84%

Section: B Moleculesmentioning

confidence: 99%

Short-range stabilizing potential for computing energies and lifetimes of temporary anions with extrapolation methods

Sommerfeld

Ehara

2015

The Journal of Chemical Physics

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“…By using complex scaling and complex absorbing potential techniques, we extended these powerful methods to describe autoionising states, such as transient anions, highly excited electronic states, and core-ionised species [183][184][185]. In addition, users can employ stabilisation techniques using charged sphere and scaled atomic charges options [186].…”

Section: Coupled Cluster Methodsmentioning

confidence: 99%

Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

Shao¹,

Gan²,

Epifanovsky³

et al. 2014

Molecular Physics

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2,698

2,077

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A summary of the technical advances that are incorporated in the fourth major release of the Q-Chem quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and openshell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr 2 dimer, exploring zeolitecatalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.Keywords quantum chemistry, software, electronic structure theory, density functional theory, electron correlation, computational modelling, Q-Chem Disciplines Chemistry CommentsThis article is from Molecular Physics: An International Journal at the Interface Between Chemistry and Physics 113 (2015): 184, doi:10.1080/00268976.2014. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. Authors 185A summary of the technical advances that are incorporated in the fourth major release of the Q-CHEM quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly corre...

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“…However, the width computed with the type III-Coulomb method is consistently too large, and does not converge to the correct limit with increasing basis set size and level of theory. The performance of the type III method on method position width Stieltjes imaging 46 2.23 0.40 Schwinger variational + ADC(3) optical potential 47 2.534 0.536 3rd order decouplings of dilated electron propogator 48 2.11 0.18 EOM-EA-CCSD stabilization (aug-cc-pV5Z) 49 2.49 0.5 CAP EOM-EA-CCSD (1st order, aug-cc-pVQZ + 3s3p3d) 50 2 this particular problem is better than might be expected from the application to the model potential. This may be because, unlike in the case of the model potential, the width is almost an order of magnitude smaller than the position.…”

Section: A Evaluation Of the Type Iii-coulomb Methodsmentioning

confidence: 99%

Stabilizing potentials in bound state analytic continuation methods for electronic resonances in polyatomic molecules

White

Head‐Gordon

McCurdy

2017

The Journal of Chemical Physics

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The computation of Siegert energies by analytic continuation of bound state energies has recently been applied to shape resonances in polyatomic molecules by several authors. We critically evaluate a recently proposed analytic continuation method based on low order (type III) Padé approximants as well as an analytic continuation method based on high order (type II) Padé approximants. We compare three classes of stabilizing potentials: Coulomb potentials, Gaussian potentials, and attenuated Coulomb potentials. These methods are applied to a model potential where the correct answer is known exactly and to the 2 Π g shape resonance of N − 2 which has been studied extensively by other methods. Both the choice of stabilizing potential and method of analytic continuation prove to be important to the accuracy of the results. We conclude that an attenuated Coulomb potential is the most effective of the three for bound state analytic continuation methods. With the proper potential, such methods show promise for algorithmic determination of the positions and widths of molecular shape resonances.

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Complex absorbing potentials within EOM-CC family of methods: Theory, implementation, and benchmarks

Cited by 136 publications

References 136 publications

Short-range stabilizing potential for computing energies and lifetimes of temporary anions with extrapolation methods

Short-range stabilizing potential for computing energies and lifetimes of temporary anions with extrapolation methods

Advances in molecular quantum chemistry contained in the Q-Chem 4 program package

Stabilizing potentials in bound state analytic continuation methods for electronic resonances in polyatomic molecules

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