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

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. As in previous studies, we find that the most efficient way to obtain HLCs is to combine (T) from conventional CCSD(T) calculations with explicitly correlated CCSD-F12–MP2-F12 differences.

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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

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.

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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

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.

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Explicitly correlated coupled cluster calculations of the dissociation energies and barriers to concerted hydrogen exchange of (HF)n oligomers (n = 2,3,4,5)

Molecular Physics ◽

10.1080/00268979809482299 ◽

1998 ◽

Vol 94 (1) ◽

pp. 105-119 ◽

Cited By ~ 2

Author(s):

WIM KLOPPER ◽

MARTIN QUACK ◽

MARTIN SUHM

Keyword(s):

Hydrogen Exchange ◽

Coupled Cluster ◽

Dissociation Energies ◽

Cluster Calculations ◽

Explicitly Correlated ◽

Coupled Cluster Calculations

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A computational study for the reaction mechanism of metal-free cyanomethylation of aryl alkynoates with acetonitrile

RSC Advances ◽

10.1039/d1ra01649k ◽

2021 ◽

Vol 11 (30) ◽

pp. 18246-18251

Author(s):

Selçuk Eşsiz

Keyword(s):

Density Functional Theory ◽

Reaction Mechanism ◽

Density Functional ◽

Computational Study ◽

Coupled Cluster ◽

Functional Theory ◽

Metal Free ◽

Coupled Cluster Methods ◽

High Level ◽

Cluster Methods

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].

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Visible-light Photoresponse of Nitrogen-doped TiO2: Excited State Studies Using Time-dependent Density Functional Theory and Equation-of-Motion Coupled Cluster Methods

MRS Proceedings ◽

10.1557/proc-1263-y04-06 ◽

2010 ◽

Vol 1263 ◽

Author(s):

Niranjan Govind ◽

Roger Rousseau ◽

Amity Andersen ◽

Karol Kowalski

Keyword(s):

Excited State ◽

Density Functional ◽

Equation Of Motion ◽

Coupled Cluster ◽

Functional Theory ◽

Experimental Findings ◽

High Level ◽

Cluster Methods ◽

Compare And Contrast

AbstractTo shed light on the nature of the electronic states at play in N-doped TiO2 nanoparticles, we have performed detailed ground and excited state calculations on pure and N-doped TiO2 rutile using an embedding model. We have validated our model by comparing ground-state embedded results with those obtained from periodic DFT calculations. Our results are consistent with periodic calculations. Using this embedding model we have performed B3LYP based TDDFT calculations of the excited state spectrum. We have also studied the lowest excitations using high-level equation-of-motion coupled cluster (EOMCC) approaches involving all single and inter-band double excitations. We compare and contrast the nature of the excitations in detail for the pure and doped systems using these calculations. Our calculations indicate a lowering of the bandgap and confirm the role of the N3- states on the UV/Vis spectrum of N-doped TiO2 rutile supported by experimental findings.

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