scholarly journals Cover Feature: Directionality of Halogen Bonds: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study (ChemPhysChem 15/2019)

ChemPhysChem ◽  
2019 ◽  
Vol 20 (15) ◽  
pp. 1906-1906
Author(s):  
Nasim Orangi ◽  
Kiamars Eskandari ◽  
Joseph C. R. Thacker ◽  
Paul L. A. Popelier
Keyword(s):  
Relative Energy ◽  
Halogen Bonds ◽  
Energy Gradient ◽  
Interacting Quantum Atoms

scholarly journals Directionality of Halogen Bonds: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study

ChemPhysChem ◽  
2019 ◽  
Vol 20 (15) ◽  
pp. 1922-1930 ◽  
Author(s):  
Nasim Orangi ◽  
Kiamars Eskandari ◽  
Joseph C. R. Thacker ◽  
Paul L. A. Popelier
Keyword(s):  
Relative Energy ◽  
Halogen Bonds ◽  
Energy Gradient ◽  
Interacting Quantum Atoms

scholarly journals An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study of the Halogen Bond with Explicit Analysis of Electron Correlation

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2674 ◽  
Author(s):  
Ibon Alkorta ◽  
Arnaldo F. Silva ◽  
Paul L. A. Popelier
Keyword(s):  
Complex Formation ◽  
Electron Correlation ◽  
Correlation Energy ◽  
Halogen Bond ◽  
Relative Energy ◽  
Space Correlation ◽  
Energy Profiles ◽  
Energy Gradient ◽  
Explicit Analysis ◽  
Interacting Quantum Atoms

Energy profiles of seven halogen-bonded complexes were analysed with the topological energy partitioning called Interacting Quantum Atoms (IQA) at MP4(SDQ)/6–31 + G(2d,2p) level of theory. Explicit interatomic electron correlation energies are included in the analysis. Four complexes combine X2 (X = Cl or F) with HCN or NH3, while the remaining three combine ClF with HCN, NH3 or N2. Each complex was systematically deformed by translating the constituent molecules along its central axis linking X and N, and reoptimising its remaining geometry. The Relative Energy Gradient (REG) method (Theor. Chem. Acc. 2017, 136, 86) then computes which IQA energies most correlate with the total energy during the process of complex formation and further compression beyond the respective equilibrium geometries. It turns out that the covalent energy (i.e., exchange) of the halogen bond, X…N, itself drives the complex formation. When the complexes are compressed from their equilibrium to shorter X…N distance then the intra-atomic energy of N is in charge. When the REG analysis is restricted to electron correlation then the interatomic correlation energy between X and N again drives the complex formation, and the complex compression is best described by the destabilisation of the through-space correlation energy between N and the “outer” halogen.

scholarly journals A relative energy gradient (REG) study of the nitrogen inversion in N-substituted aziridines

2020 ◽  
Vol 758 ◽  
pp. 137927
Author(s):  
Ibon Alkorta ◽  
José Elguero ◽  
Paul L.A. Popelier
Keyword(s):  
Relative Energy ◽  
Nitrogen Inversion ◽  
Energy Gradient

scholarly journals Towards an Atomistic Understanding of Polymorphism in Molecular Solids

2021 ◽  
Author(s):  
Arturo Sauza-de la Vega ◽  
Leonardo J. Duarte ◽  
arnaldo silva ◽  
Jonathan Skelton ◽  
Tomás Rocha-Rinza ◽  
...  
Keyword(s):  
Decomposition Analysis ◽  
Relative Energy ◽  
Energy Partitioning ◽  
Energy Decomposition Analysis ◽  
Molecular Solids ◽  
Total System ◽  
Energy Gradient ◽  
A New Technique ◽  
The Many ◽  
Energy Balances

Many chemical phenomena are ultimately due to energy balances between atoms. In order to reach firm and clear conclusions one needs a reliable energy decomposition analysis (EDA). The Interacting Quantum Atoms (IQA) energy partitioning method is one of the most recent EDA methods. IQA is a topological energy partitioning that generates well-defined intra- and interatomic contributions, of steric, electrostatic or covalent (exchange) character. IQA has a minimal and powerful architecture and does not suffer from a number of conceptual and practical problems that plague the more traditional non-topological EDAs (<i>Chem. Soc. Rev.</i>, <b>44</b> (2015) 3177).<div><br></div><div>For the first time, our manuscript reports on a protocol for using the IQA to understand polymorphism, which we apply to the three polymorphs of succinic acid (SA), including the unusual polymorph that was recently discovered serendipitously (<i>CrystEngComm</i>, <b>20</b> (2018) 3971). The many intra- and interatomic energy terms from the EDA scheme are processed using a new technique that we developed called the Relative Energy Gradient (REG) method, which clearly identifies the atoms and corresponding energetic terms that govern the behaviour of the total system, in a minimal and unbiased way. <br></div>

scholarly journals Towards an Atomistic Understanding of Polymorphism in Molecular Solids

2021 ◽  
Author(s):  
Arturo Sauza-de la Vega ◽  
Leonardo J. Duarte ◽  
arnaldo silva ◽  
Jonathan Skelton ◽  
Tomás Rocha-Rinza ◽  
...  
Keyword(s):  
Decomposition Analysis ◽  
Relative Energy ◽  
Energy Partitioning ◽  
Energy Decomposition Analysis ◽  
Molecular Solids ◽  
Total System ◽  
Energy Gradient ◽  
A New Technique ◽  
The Many ◽  
Energy Balances

Many chemical phenomena are ultimately due to energy balances between atoms. In order to reach firm and clear conclusions one needs a reliable energy decomposition analysis (EDA). The Interacting Quantum Atoms (IQA) energy partitioning method is one of the most recent EDA methods. IQA is a topological energy partitioning that generates well-defined intra- and interatomic contributions, of steric, electrostatic or covalent (exchange) character. IQA has a minimal and powerful architecture and does not suffer from a number of conceptual and practical problems that plague the more traditional non-topological EDAs (<i>Chem. Soc. Rev.</i>, <b>44</b> (2015) 3177).<div><br></div><div>For the first time, our manuscript reports on a protocol for using the IQA to understand polymorphism, which we apply to the three polymorphs of succinic acid (SA), including the unusual polymorph that was recently discovered serendipitously (<i>CrystEngComm</i>, <b>20</b> (2018) 3971). The many intra- and interatomic energy terms from the EDA scheme are processed using a new technique that we developed called the Relative Energy Gradient (REG) method, which clearly identifies the atoms and corresponding energetic terms that govern the behaviour of the total system, in a minimal and unbiased way. <br></div>

scholarly journals A relative energy gradient (REG) study of the planar and perpendicular torsional energy barriers in biphenyl

2018 ◽  
Vol 138 (1) ◽  
Author(s):  
Paul L. A. Popelier ◽  
Peter I. Maxwell ◽  
Joseph C. R. Thacker ◽  
Ibon Alkorta
Keyword(s):  
Relative Energy ◽  
Energy Barriers ◽  
Torsional Energy ◽  
Energy Gradient
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