scholarly journals Physical Nature of Differential Spin-State Stabilization of Carbenes by Hydrogen and Halogen Bonding: A Domain-Based Pair Natural Orbital Coupled Cluster Study

2019 ◽  
Vol 123 (24) ◽  
pp. 5081-5090 ◽  
Author(s):  
Reza Ghafarian Shirazi ◽  
Frank Neese ◽  
Dimitrios A. Pantazis ◽  
Giovanni Bistoni
Keyword(s):  
Spin State ◽  
Physical Nature ◽  
Halogen Bonding ◽  
Coupled Cluster ◽  
Natural Orbital

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

2017 ◽  
Author(s):  
Manoj Kumar Kesharwani ◽  
Nitai Sylvetsky ◽  
Debashree Manna ◽  
Jan M.L. Martin
Keyword(s):  
Dissociation Energy ◽  
Noncovalent Interactions ◽  
Halogen Bonding ◽  
Coupled Cluster ◽  
Dissociation Energies ◽  
Iodine Species ◽  
Explicitly Correlated ◽  
High Level ◽  
Cluster Methods ◽  
Small Separation

<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. 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.</p>

scholarly journals Assessing the Orbital Contribution in the “Spodium Bond” by Natural Orbital for Chemical Valence-Charge Displacement Analysis

2021 ◽  
Author(s):  
Gianluca Ciancaleoni ◽  
Luca Rocchigiani
Keyword(s):  
Weak Interactions ◽  
Halogen Bonding ◽  
Lewis Base ◽  
Natural Orbital ◽  
Orbital Contribution ◽  
Metal Base ◽  
Displacement Analysis ◽  
Group 12 ◽  
Base Distance ◽  
Charge Displacement

<p>The term “spodium bond” (SpB) has been recently proposed for the non-coordinative interaction between a polarised group 12 metal and a mild Lewis base. In most of the systems showing short metal-donor distances, however, SpB coexists with other weak interactions, including hydrogen and halogen bonding. Here we show their mutual importance can be probed by dissecting the orbital component of the interaction through the Natural Orbital for Chemical Valence-Charge Displacement analysis. NOCV-CD gives us straightforward snapshots of relative energies and electrons involved, either for model and “real” adducts, allowing us to demonstrate the lack of a direct correlation between a favourable metal-base distance and the presence of an orbital contribution for the SpB.</p>

A domain-based local pair natural orbital implementation of the equation of motion coupled cluster method for electron attached states

2019 ◽  
Vol 150 (16) ◽  
pp. 164123 ◽  
Author(s):  
Achintya Kumar Dutta ◽  
Masaaki Saitow ◽  
Baptiste Demoulin ◽  
Frank Neese ◽  
Róbert Izsák
Keyword(s):  
Equation Of Motion ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Natural Orbital ◽  
Local Pair

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

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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