To Multireference or not to Multireference: That is the Question?

Bartlett, Rodney J.

doi:10.3390/i3060579

Cited by 82 publications

(43 citation statements)

References 99 publications

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“…[32][33][34] Subsequent developments [35][36][37][38][39][40][41][42][43] of the EOM methodology with a CC reference wave function enabled accurate calculations of electron attached, ionized, and spinflipped states, as discussed in detail in several reviews. [44][45][46][47][48][49][50][51][52] By combining different EOM-CC methods, one can describe ionization from open-shell and electronically excited states. 51 Calculated using highly correlated wave functions, EOM-CC Dyson orbitals include both correlation and orbital relaxation effects.…”

Section: Introductionmentioning

confidence: 99%

Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals

Oana

Krylov

2009

The Journal of Chemical Physics

177

226

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We report total and differential cross sections for photodetachment from negative ions using Dyson orbitals calculated from equation-of-motion coupled-cluster wave functions and free wave description of the detached electron. The energy dependence of the cross sections is reproduced well, however, the accuracy of absolute values varies. For F(-), C(-), NH(2)(-), and H(-), the calculated cross sections are within the error bars from the experimental values, whereas the errors for Li(-) and OH(-) are about 20%. The largest errors are observed for O(-) and O(2)(-) for which the calculated cross sections differ from the experimental ones by factors of 3 and 2, respectively. Calculated anisotropy parameters for atomic anions exhibit too slow decrease, which suggests that the diffuseness of the computed Dyson orbitals is underestimated. Moreover, in the asymptotic region, the orbitals exhibit artifactual oscillations probably due to the limitations of Gaussian basis sets. The analysis of the trends in the experimental anisotropy parameters suggests that the interaction of the detached electron with the core, which is neglected in the present model, is important.

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Section: Introductionmentioning

confidence: 99%

Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals

Oana

Krylov

2009

The Journal of Chemical Physics

177

226

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“…[10][11][12][13][14][15][16] Similar ͑or even identical͒ equations can be derived within linear response CC [17][18][19][20] or symmetry-adapted cluster configuration interaction formalisms. [10][11][12][13][14][15][16] Similar ͑or even identical͒ equations can be derived within linear response CC [17][18][19][20] or symmetry-adapted cluster configuration interaction formalisms.…”

Section: Introductionmentioning

confidence: 99%

A noniterative perturbative triples correction for the spin-flipping and spin-conserving equation-of-motion coupled-cluster methods with single and double substitutions

Manohar

Krylov

2008

The Journal of Chemical Physics

157

195

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A noniterative N (7) triples correction for the equation-of-motion coupled-cluster method with single and double substitutions (CCSD) is presented. The correction is derived by second-order perturbation treatment of the similarity-transformed CCSD Hamiltonian. The spin-conserving variant of the correction is identical to the triples correction of Piecuch and co-workers [Mol. Phys. 104, 2149 (2006)] derived within method-of-moments framework and is not size intensive. The spin-flip variant of the correction is size intensive. The performance of the correction is demonstrated by calculations of electronic excitation energies in methylene, nitrenium ion, cyclobutadiene, ortho-, meta-, and para-benzynes, 1,2,3-tridehydrobenzene, as well as C-C bond breaking in ethane. In all cases except cyclobutadiene, the absolute values of the correction for energy differences were 0.1 eV or less. In cyclobutadiene, the absolute values of the correction were as large as 0.4 eV. In most cases, the correction reduced the errors against the benchmark values by about a factor of 2-3, the absolute errors being less than 0.04 eV.

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“…For a detailed discussion, we refer the reader to Ref. [34]. Equation-of-motion methods (see [26,27] for recent reviews) avoid these problems as they exhibit the transparency and computational simplicity of single-reference coupled-cluster theory.…”

Section: Coupled-cluster Theory and Equations-of-motion For Nucleimentioning

confidence: 99%

Toward open-shell nuclei with coupled-cluster theory

et al. 2011

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We develop a new method based on equation-of-motion coupled-cluster theory to describe properties of open-shell nuclei with A ± 2 nucleons outside a closed shell. We perform proof-of-principle calculations for the ground states of the helium isotopes 3−6 He and the first excited 2 + state in 6 He. The comparison with exact results from matrix diagonalization in small model spaces demonstrates the accuracy of the coupled-cluster methods. Three-particle-one-hole excitations of 4 He play an important role for the accurate description of 6 He. For the open-shell nucleus 6 He, the computational cost of the method is comparable with the coupled-cluster singles-and-doubles approximation while its accuracy is similar to coupled-cluster with singles, doubles and triples excitations.

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To Multireference or not to Multireference: That is the Question?

Cited by 82 publications

References 99 publications

Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals

Cross sections and photoelectron angular distributions in photodetachment from negative ions using equation-of-motion coupled-cluster Dyson orbitals

A noniterative perturbative triples correction for the spin-flipping and spin-conserving equation-of-motion coupled-cluster methods with single and double substitutions

Toward open-shell nuclei with coupled-cluster theory

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