The S66 Non-Covalent Interactions Benchmark Reconsidered Using Explicitly Correlated Methods Near the Basis Set Limit

<p>The S66 benchmark for noncovalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 “high-level corrections” are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66x8 problem set in particular, and for accurate calculations on noncovalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, while half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.</p>

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The S66 noncovalent interactions benchmark reconsidered using explicitly correlated methods near the basis set limit

10.26434/chemrxiv.5597905 ◽

2017 ◽

Author(s):

Manoj Kumar Kesharwani ◽

Amir Karton ◽

Nitai Sylvetsky ◽

Jan M. L. Martin

Keyword(s):

Noncovalent Interactions ◽

Computational Cost ◽

The Other ◽

Basis Set ◽

Basis Sets ◽

Final Version ◽

Explicitly Correlated ◽

Explicitly Correlated Methods ◽

The One ◽

High Level

<p>[Final version of record available at http://dx.doi.org/10.1071/CH17588]</p><p>The S66 benchmark for noncovalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 “high-level corrections” are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66x8 problem set in particular, and for accurate calculations on noncovalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, while half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.<br></p>

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The S66 noncovalent interactions benchmark reconsidered using explicitly correlated methods near the basis set limit

10.26434/chemrxiv.5597905.v2 ◽

2017 ◽

Author(s):

Manoj Kumar Kesharwani ◽

Amir Karton ◽

Nitai Sylvetsky ◽

Jan M. L. Martin

Keyword(s):

Noncovalent Interactions ◽

Computational Cost ◽

The Other ◽

Basis Set ◽

Basis Sets ◽

Other Hand ◽

Explicitly Correlated ◽

Explicitly Correlated Methods ◽

The One ◽

High Level

<p>The S66 benchmark for noncovalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 “high-level corrections” are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66x8 problem set in particular, and for accurate calculations on noncovalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, while half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.<br></p>

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The X40x10 Halogen Bonding Benchmark Revisited: Surprising Importance of (n-1)d Subvalence Correlation

10.26434/chemrxiv.5580007.v2 ◽

2018 ◽

Author(s):

Manoj Kumar Kesharwani ◽

Nitai Sylvetsky ◽

Debashree Manna ◽

Jan M.L. Martin

Keyword(s):

Noncovalent Interactions ◽

Halogen Bonding ◽

Basis Set ◽

Basis Sets ◽

Coupled Cluster ◽

Dissociation Energies ◽

Explicitly Correlated ◽

Two Factors ◽

High Level ◽

Cluster Methods

<p>We have re-evaluated the X40x10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)–MP2 “high-level corrections” (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies, and turns out to be more important for noncovalent interactions than is generally realized; ; (n-1)sp subvalence correlation is much less important. The (n-1)d subvalence term is dominated by core-valence correlation; with the smaller cc-pVDZ-F12-PP and cc-pVTZ-F12-PP basis sets, basis set convergence for the core-core contribution becomes sufficiently erratic that it may compromise results overall. The two factors conspire to generate discrepancies of up to 0.9 kcal/mol (0.16 kcal/mol RMS) between the original X40x10 data and the present revision.</p>

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A Halomanganates(II) with P,P’-Diprotonated Bis(2-Diphenylphosphinophenyl)ether: Wavelength-Excitation Dependence of the Quantum Yield and Role of the Non-Covalent Interactions

International Journal of Molecular Sciences ◽

10.3390/ijms22136873 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6873

Author(s):

Alexey S. Berezin

Keyword(s):

Quantum Yield ◽

Excitation Energy ◽

The Other ◽

Green Luminescence ◽

Radiative Relaxation ◽

Bright Green ◽

Non Covalent Interactions ◽

The One ◽

Covalent Interactions

A [H2DPEphos][MnX4] [X = Br, Cl] tetrahalomanganates(II) with P,P’-diprotonated bis[2-(diphenylphosphino)phenyl]ether cation has been designed and investigated in photophysics and EPR terms. The complexes exhibit a green luminescence resulted from the Mn(II) d–d transitions (4T1→6A1) with the wavelength-excitation dependence of the quantum yield. The solid [H2DPEphos][MnBr4] complex exhibits a bright green phosphorescence (λmax = 515 nm) with the high luminescence quantum yield depending on the excitation energy whereas the solid [H2DPEphos][MnCl4] complex exhibits a very weak phosphorescence (λmax = 523 nm). The unexpected shorter luminescence lifetime for the [H2DPEphos][MnCl4] than for the [H2DPEphos][MnBr4] at 300 K can be a result of the higher non-radiative relaxation contribution. On the one hand, the non-covalent PH…X(Mn) interactions quench the manganese(II) luminescence. On the other hand, the PH…X(Mn) interactions are a pathway of the excitation transfer from [H2DPEphos]2+ to [MnX4]2−.

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The X40x10 Halogen Bonding Benchmark Revisited: Surprising Importance of (n-1)d Subvalence Correlation

10.26434/chemrxiv.5580007 ◽

2018 ◽

Author(s):

Manoj Kumar Kesharwani ◽

Nitai Sylvetsky ◽

Debashree Manna ◽

Jan M.L. Martin

Keyword(s):

Noncovalent Interactions ◽

Halogen Bonding ◽

Basis Set ◽

Basis Sets ◽

Coupled Cluster ◽

Dissociation Energies ◽

Explicitly Correlated ◽

Two Factors ◽

High Level ◽

Cluster Methods

<p>We have re-evaluated the X40x10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)–MP2 “high-level corrections” (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies, and turns out to be more important for noncovalent interactions than is generally realized; ; (n-1)sp subvalence correlation is much less important. The (n-1)d subvalence term is dominated by core-valence correlation; with the smaller cc-pVDZ-F12-PP and cc-pVTZ-F12-PP basis sets, basis set convergence for the core-core contribution becomes sufficiently erratic that it may compromise results overall. The two factors conspire to generate discrepancies of up to 0.9 kcal/mol (0.16 kcal/mol RMS) between the original X40x10 data and the present revision.</p>

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Mixed Basis Sets for Atomic Calculations

Atoms ◽

10.3390/atoms7030092 ◽

2019 ◽

Vol 7 (3) ◽

pp. 92

Author(s):

Mikhail Kozlov ◽

Ilya Tupitsyn

Keyword(s):

Numerical Methods ◽

Linear Dependence ◽

Unitary Operator ◽

The Other ◽

Basis Set ◽

Basis Sets ◽

Rapid Convergence ◽

Occupation Numbers ◽

The One ◽

Single Set

Many numerical methods of atomic calculations use one-electron basis sets. These basis sets must meet rather contradictory requirements. On the one hand, they must include physically justified orbitals, such as Dirac–Fock ones, for the one-electron states with high occupation numbers. On the other hand, they must ensure rapid convergence of the calculations in respect to the size of the basis set. It is difficult to meet these requirements using a single set of orbitals, while merging different subsets may lead to linear dependence and other problems. We suggest a simple unitary operator that allows such merging without aforementioned complications. We demonstrated robustness of the method on the examples of Fr and Au.

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On the Use of Popular Basis Sets: Impact of the Intramolecular Basis Set Superposition Error

Molecules ◽

10.3390/molecules24203810 ◽

2019 ◽

Vol 24 (20) ◽

pp. 3810 ◽

Cited By ~ 2

Author(s):

Ángel Vidal Vidal ◽

Luis de Vicente Poutás ◽

Olalla Nieto Faza ◽

Carlos Silva López

Keyword(s):

Small Molecules ◽

Chemical Properties ◽

Basis Set ◽

Basis Sets ◽

Basis Set Superposition Error ◽

Large Molecules ◽

Molecular Complexation ◽

Non Covalent Interactions ◽

Covalent Interactions ◽

Structure Calculations

The magnitude of intramolecular basis set superposition error (BSSE) is revealed via computing systematic trends in molecular properties. This type of error is largely neglected in the study of the chemical properties of small molecules and it has historically been analyzed just in the study of large molecules and processes dominated by non-covalent interactions (typically dimerization or molecular complexation and recognition events). In this work we try to provide proof of the broader prevalence of this error, which permeates all types of electronic structure calculations, particularly when employing insufficiently large basis sets.

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DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

10.26434/chemrxiv.8217221.v1 ◽

2019 ◽

Author(s):

Danilo Carmona ◽

Pablo Jaque ◽

Esteban Vöhringer-Martinez

Keyword(s):

Reference Value ◽

Basis Set ◽

Basis Sets ◽

Mean Deviation ◽

Bond Dissociation ◽

Dissociation Energies ◽

The Mean ◽

Experimental Values ◽

High Level ◽

Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

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1,3,5-Triaza-7-Phosphaadamantane (PTA) as a 31P NMR Probe for Organometallic Transition Metal Complexes in Solution

Molecules ◽

10.3390/molecules26051390 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1390 ◽

Cited By ~ 1

Author(s):

Ilya G. Shenderovich

Keyword(s):

Chemical Shift ◽

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Density Functional ◽

Molecular Structures ◽

Basis Sets ◽

Functional Theory ◽

Non Covalent Interactions ◽

Covalent Interactions

Due to the rigid structure of 1,3,5-triaza-7-phosphaadamantane (PTA), its 31P chemical shift solely depends on non-covalent interactions in which the molecule is involved. The maximum range of change caused by the most common of these, hydrogen bonding, is only 6 ppm, because the active site is one of the PTA nitrogen atoms. In contrast, when the PTA phosphorus atom is coordinated to a metal, the range of change exceeds 100 ppm. This feature can be used to support or reject specific structural models of organometallic transition metal complexes in solution by comparing the experimental and Density Functional Theory (DFT) calculated values of this 31P chemical shift. This approach has been tested on a variety of the metals of groups 8–12 and molecular structures. General recommendations for appropriate basis sets are reported.

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