Communication: Rigorous calculation of dissociation energies (D0) of the water trimer, (H2O)3 and (D2O)3

<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>

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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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A Comprehensive Computational Study on OCH+-Rg (Rg = He, Ne, Ar, Kr, Xe) Complexes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20030489 ◽

2003 ◽

Vol 68 (3) ◽

pp. 489-508 ◽

Cited By ~ 2

Author(s):

Yinghong Sheng ◽

Jerzy Leszczynski

Keyword(s):

Computational Study ◽

Relativistic Effects ◽

Dft Method ◽

Basis Set ◽

Rare Gas ◽

Geometrical Parameters ◽

Minor Effect ◽

Dissociation Energies ◽

Equilibrium Geometries

The equilibrium geometries, harmonic vibrational frenquencies, and the dissociation energies of the OCH+-Rg (Rg = He, Ne, Ar, Kr, and Xe) complexes were calculated at the DFT, MP2, MP4, CCSD, and CCSD(T) levels of theory. In the lighter OCH+-Rg (Rg = He, Ne, Ar) rare gas complexes, the DFT and MP4 methods tend to produce longer Rg-H+ distance than the CCSD(T) level value, and the CCSD-calculated Rg-H+ bond lengths are slightly shorter. DFT method is not reliable to study weak interaction in the OCH+-He and OCH+-Ne complexes. A qualitative result can be obtained for OCH+-Ar complex by using the DFT method; however, a higher-level method using a larger basis set is required for the quantitative predictions. For heavier atom (Kr, Xe)-containing complexes, only the CCSD method predicted longer Rg-H+ distance than that obtained at the CCSD(T) level. The DFT method can be applied to obtain the semiquantitative results. The relativistic effects are expected to have minor effect on the geometrical parameters, the H+-C stretching mode, and the dissociation energy. However, the dissociation energies are sensitive to the quality of the basis set. The nature of interaction between the OCH+ ion and Rg atoms was also analyzed in terms of the interaction energy components.

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On the Proton-Bound Noble Gas Dimers (Ng-H-Ng)+ and (Ng-H-Ng')+ (Ng, Ng'= He-Xe): Relationships betweenStructure, Stability, and Bonding Character

Molecules ◽

10.3390/molecules26051305 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1305

Author(s):

Stefano Borocci ◽

Felice Grandinetti ◽

Nico Sanna

Keyword(s):

Theoretical Calculations ◽

Noble Gas ◽

Structure Stability ◽

Covalent Bonds ◽

Dissociation Energies ◽

Non Covalent Interactions ◽

The Difference ◽

Noble Gas Dimers ◽

Covalent Interactions ◽

Cluster Level

The structure, stability, and bonding character of fifteen (Ng-H-Ng)+ and (Ng-H-Ng')+ (Ng, Ng' = He-Xe) compounds were explored by theoretical calculations performed at the coupled cluster level of theory. The nature of the stabilizing interactions was, in particular, assayed using a method recently proposed by the authors to classify the chemical bonds involving the noble-gas atoms. The bond distances and dissociation energies of the investigated ions fall in rather large intervals, and follow regular periodic trends, clearly referable to the difference between the proton affinity (PA) of the various Ng and Ng'. These variations are nicely correlated with the bonding situation of the (Ng-H-Ng)+ and (Ng-H-Ng')+. The Ng-H and Ng'-H contacts range, in fact, between strong covalent bonds to weak, non-covalent interactions, and their regular variability clearly illustrates the peculiar capability of the noble gases to undergo interactions covering the entire spectrum of the chemical bond.

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Experimental bond dissociation energies of benzylpyridinium thermometer ions determined by threshold-CID and RRKM modeling

International Journal of Mass Spectrometry ◽

10.1016/j.ijms.2017.03.002 ◽

2017 ◽

Vol 417 ◽

pp. 69-75 ◽

Cited By ~ 9

Author(s):

David Gatineau ◽

Antony Memboeuf ◽

Anne Milet ◽

Richard B. Cole ◽

Héloïse Dossmann ◽

...

Keyword(s):

Bond Dissociation Energies ◽

Bond Dissociation ◽

Dissociation Energies ◽

Thermometer Ions

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Potential Functions and Thermodynamic Properties of UC, UN, and UH

Journal of Chemistry ◽

10.1155/2020/7512737 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Shuang-Ling Tang ◽

Yu Wang ◽

Qi-Ying Xia ◽

Xue-Hai Ju

Keyword(s):

Configuration Interaction ◽

Density Functional ◽

Least Square Method ◽

Potential Functions ◽

Least Square ◽

Basis Set ◽

Dissociation Energies ◽

Anharmonicity Constant ◽

Different Temperatures ◽

Relationship Of

Potential energy surface scanning for UC, UN, and UH was performed by configuration interaction (CI), coupled cluster singles and doubles (CCSD) excitation, quadratic configuration interaction (QCISD (T)), and density functional theory PBE1 (DFT-PBE1) methods in coupling with the ECP80MWB_AVQZ + 2f basis set for uranium and 6 − 311 + G∗ for carbon, hydrogen, and nitrogen. The dissociation energies of UC, UN, and UH are 5.7960, 4.5077, and 2.6999 eV at the QCISD (T) levels, respectively. The calculated energy was fitted to the potential functions of Morse, Lennard-Jones, and Rydberg by using the least square method. The anharmonicity constant of UC is 0.0047160. The anharmonic frequency of UC is 780.27 cm−1 which was obtained based on the PBE1 results. For UN, the anharmonicity constant is 0.0049827. The anharmonic frequency is 812.65 cm−1 which was obtained through the PBE1 results. For UH, the anharmonicity constant is 0.017300. The anharmonic frequency obtained via the QCISD (T) results is 1449.8 cm−1. The heat capacity and entropy in different temperatures were calculated using anharmonic frequencies. These properties are in good accordance with the direct DFT-UPBE1 results (for UC and UN) and QCISD (T) results (for UH). The relationship of entropy with temperature was established.

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Electron affinities of a homologous series of tertiary alkyl radicals and their C–H bond dissociation energies (BDEs)

Tetrahedron ◽

10.1016/j.tet.2008.12.043 ◽

2009 ◽

Vol 65 (8) ◽

pp. 1655-1659 ◽

Cited By ~ 2

Author(s):

Panayiotis S. Petrou ◽

Athanassios V. Nicolaides

Keyword(s):

Homologous Series ◽

Bond Dissociation Energies ◽

Electron Affinities ◽

Alkyl Radicals ◽

Bond Dissociation ◽

Dissociation Energies ◽

Tertiary Alkyl

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Directionality and the Role of Polarization in Electric Field Effects on Radical Stability

Australian Journal of Chemistry ◽

10.1071/ch16579 ◽

2017 ◽

Vol 70 (4) ◽

pp. 367 ◽

Cited By ~ 15

Author(s):

Ganna Gryn'ova ◽

Michelle L. Coote

Keyword(s):

Electric Field ◽

External Electric Field ◽

Radical Reactions ◽

Electric Field Effects ◽

Dissociation Energies ◽

Barrier Heights ◽

Diol Dehydratase ◽

Group A ◽

Activity Of Enzymes ◽

The Stability

Accurate quantum-chemical calculations are used to analyze the effects of charges on the kinetics and thermodynamics of radical reactions, with specific attention given to the origin and directionality of the effects. Conventionally, large effects of the charges are expected to occur in systems with pronounced charge-separated resonance contributors. The nature (stabilization or destabilization) and magnitude of these effects thus depend on the orientation of the interacting multipoles. However, we show that a significant component of the stabilizing effects of the external electric field is largely independent of the orientation of external electric field (e.g. a charged functional group, a point charge, or an electrode) and occurs even in the absence of any pre-existing charge separation. This effect arises from polarization of the electron density of the molecule induced by the electric field. This polarization effect is greater for highly delocalized species such as resonance-stabilized radicals and transition states of radical reactions. We show that this effect on the stability of such species is preserved in chemical reaction energies, leading to lower bond-dissociation energies and barrier heights. Finally, our simplified modelling of the diol dehydratase-catalyzed 1,2-hydroxyl shift indicates that such stabilizing polarization is likely to contribute to the catalytic activity of enzymes.

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