Basis set convergence and performance of density functional theory including exact exchange contributions for geometries and harmonic frequencies

Martin, Jan M. L.; El-Yazal, Jamal; François, J

doi:10.1080/00268979500102841

Cited by 173 publications

(109 citation statements)

References 48 publications

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“…The C-F bond lengths are 0.02 A smaller than for benzyl fluoride (6), in the MP2/6-3 1G" structure as well. The C-H and C-C bond lengths of the phenyl group are rather close to those claimed to be the best (corrected) theoretical values for benzene itself (31). The exocyclic C-C bond is somewhat shorter in the conformer in which the C-H bond lies in the phenyl plane, consistent with stronger U,T withdrawal in this conformer.…”

Section: Qualitative Discussion Of the Internal Rotational Potential supporting

confidence: 65%

Theoretical and experimental approaches to the effects of solvation on the small internal rotational potential of benzal fluoride

Schaefer¹,

Bernard²,

Bekkali³

et al. 1996

Can. J. Chem.

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Abstract:The internal rotational potential for benzal fluoride is computed at various levels of molecular orbital theory, including correlation-gradient, MP2 (frozen core) methods. The perturbations of the potential caused by solvents are calculated with the Onsager model (ellipsoidal cavity with I = 6 in the multipole expansion) as well as with the self-consistent isodensitypolarizable continuum model (SCI-PCM). Analysis of the 'H and "F nuclear magnetic resonance spectra in cyclohexane-'I,2 and acetone-d6 solutions yields long-range spin-spin coupling constants from which the expectation values of sin2+ can be derived. These expectation values can be compared with those calculated from the theoretical internal rotational potential. Reasonable agreement is found for potentials obtained from MP216-3 IG* approaches in both solvent models. Long-range coupling constants between I9F and nuclei are also reported and provide very rough checks of the (sin2+) values. For the isolated molecule an additivity scheme based on the potential for benzyl fluoride reproduces much of the potential for benzal fluoride except for a deviation caused by the rather larger relative magnitude of the fourfold component in the latter. The minimum in the potential for benzal fluoride occurs for a torsional angle, +, of 90". corresponding to aconformation in which the C-H bond of the side chain lies in a plane perpendicular to the phenyl plane and is rationalized on the basis of electrostatic forces. The conformations of minimum energy for the benzyl and benzal fluorides and chlorides are compared and contrasted.The magnitudes of the internal potentials of the fluorides are only a little larger than thermal energies at 300 K and can become smaller than the latter in solution.

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Section: Qualitative Discussion Of the Internal Rotational Potential supporting

confidence: 65%

Theoretical and experimental approaches to the effects of solvation on the small internal rotational potential of benzal fluoride

Schaefer¹,

Bernard²,

Bekkali³

et al. 1996

Can. J. Chem.

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“…This approach is known to provide equilibrium geometries and related vibrational properties of quality comparable to that achieved at the benchmark CCSD(T) theoretical level [69]. All HF, DFT, OVGF, CCSD(T)…”

Section: Computationsmentioning

confidence: 99%

Study of the photoelectron and electron momentum spectra of cyclopentene using benchmark Dyson orbital theories

Huang

Ning

Deng

et al. 2008

Phys. Chem. Chem. Phys.

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Abstract:A complete study of the valence electronic structure and related electronic excitation properties of cyclopentene in its C s ground state geometry is presented. Ionization spectra obtained from this compound by means of photoelectron spectroscopy (He I and He II) and Electron Momentum Spectroscopy have been analyzed in details up to electron binding energies of 30 eV using one-particle Green's function (1p-GF) theory along with the outer-valence (OVGF) and the third-order algebraic diagrammatic construction [ADC(3)] schemes. The employed geometries derive from DFT/B3LYP calculations in conjunction with the aug-cc-pVTZ basis set, and closely approach the structures inferred from experiments employing microwave spectroscopy or electron diffraction in the gas phase. The 1p-GF/ADC (3) calculations indicate that the orbital picture of ionization breaks down at binding energies larger 2 than ~17 eV in the inner-valence region, and that the outer-valence 7a′ orbital is also subject to a significant dispersion of the ionization intensity over shake-up states. This study confirms further the rule that OVGF pole strengths smaller than 0.85 foretell a breakdown of the orbital picture of ionization at the ADC(3) level. Spherically averaged (e, 2e) electron momentum distributions at an electron impact energy of 1200 eV that were experimentally inferred from an angular analysis of EMS intensities have been interpreted by comparison with accurate simulations employing ADC(3) Dyson orbitals. Very significant discrepancies were observed with momentum distributions obtained from several outer-valence ionization bands using standard Kohn-Sham orbitals.

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“…43 Harmonic vibrational energies and zero-point energies were computed at the same level. The main motivation for using DFT ͑B3LYP͒ at this stage is that for strongly conjugated hydrocarbon molecules the computed structures and vibrational frequencies are known to be very much comparable 44 to results obtained by means of CCSD͑T͒ ͑Ref. 45͒ ͑coupled cluster ansatz including single and double electronic excitations and supplemented by a perturbative treatment of triple excitations͒.…”

Section: Methodology and Computationsmentioning

confidence: 99%

A benchmark theoretical study of the electronic ground state and of the singlet-triplet split of benzene and linear acenes

Hajgató

Szieberth

Geerlings

et al. 2009

The Journal of Chemical Physics

197

216

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A benchmark theoretical study of the electronic ground state and of the vertical and adiabatic singlet-triplet ͑ST͒ excitation energies of benzene ͑n =1͒ and n-acenes ͑C 4n+2 H 2n+4 ͒ ranging from naphthalene ͑n =2͒ to heptacene ͑n =7͒ is presented, on the ground of single-and multireference calculations based on restricted or unrestricted zero-order wave functions. High-level and large scale treatments of electronic correlation in the ground state are found to be necessary for compensating giant but unphysical symmetry-breaking effects in unrestricted single-reference treatments. The composition of multiconfigurational wave functions, the topologies of natural orbitals in symmetry-unrestricted CASSCF calculations, the T1 diagnostics of coupled cluster theory, and further energy-based criteria demonstrate that all investigated systems exhibit a 1 A g singlet closed-shell electronic ground state. Singlet-triplet ͑S 0 -T 1 ͒ energy gaps can therefore be very accurately determined by applying the principles of a focal point analysis onto the results of a series of single-point and symmetry-restricted calculations employing correlation consistent cc-pVXZ basis sets ͑X=D, T, Q, 5͒ and single-reference methods ͓HF, MP2, MP3, MP4SDQ, CCSD, CCSD͑T͔͒ of improving quality. According to our best estimates, which amount to a dual extrapolation of energy differences to the level of coupled cluster theory including single, double, and perturbative estimates of connected triple excitations ͓CCSD͑T͔͒ in the limit of an asymptotically complete basis set ͑cc-pVϱZ͒, the S 0 -T 1 vertical excitation energies of benzene ͑n =1͒ and n-acenes ͑n =2-7͒ amount to 100.79, 76.28, 56.97, 40.69, 31.51, 22.96, and 18.16 kcal/mol, respectively. Values of 87.02, 62.87, 46.22, 32.23, 24.19, 16.79, and 12.56 kcal/mol are correspondingly obtained at the CCSD͑T͒ / cc-pVϱZ level for the S 0 -T 1 adiabatic excitation energies, upon including B3LYP/cc-PVTZ corrections for zero-point vibrational energies. In line with the absence of Peierls distortions, extrapolations of results indicate a vanishingly small S 0 -T 1 energy gap of 0 to ϳ4 kcal/ mol ͑ϳ0.17 eV͒ in the limit of an infinitely large polyacene.

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Basis set convergence and performance of density functional theory including exact exchange contributions for geometries and harmonic frequencies

Cited by 173 publications

References 48 publications

Theoretical and experimental approaches to the effects of solvation on the small internal rotational potential of benzal fluoride

Theoretical and experimental approaches to the effects of solvation on the small internal rotational potential of benzal fluoride

Study of the photoelectron and electron momentum spectra of cyclopentene using benchmark Dyson orbital theories

A benchmark theoretical study of the electronic ground state and of the singlet-triplet split of benzene and linear acenes

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