Molecular Structures of 10-Valence Electron Species. 4. Potential Energy Surfaces and Properties of HSiX+(X = O, S, Se)

1996 ◽  
Vol 100 (18) ◽  
pp. 7361-7366 ◽  
Author(s):  
Andrzej Nowek ◽  
Jerzy Leszczyński
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Valence Electron ◽  
Molecular Structures ◽  
Energy Surfaces

scholarly journals Computational Study of Inversion-topomerization Pathways in 1,3-Dimethylcyclohexane and 1,4-Dimethylcyclohexane: Ab Initio Conformational Analysis

2020 ◽  
Author(s):  
Huiting Bian ◽  
Yifan Zhang ◽  
Yongjin Wang ◽  
Jun Zhao ◽  
Xiaohui Ruan ◽  
...  
Keyword(s):  
Potential Energy ◽  
Conformational Analysis ◽  
Potential Energy Surfaces ◽  
Computational Study ◽  
Three Dimensional ◽  
Boltzmann Distribution ◽  
Molecular Structures ◽  
Stationary Points ◽  
Energy Surfaces ◽  
Cis And Trans

This work concerns the typical conformational behaviors for di-substituted cyclohexanes that inherently depend on spatial orientations of side chains in flexible cyclic ring. The 1,3-dimethylcyclohexane and 1,4-dimethylcyclohexane in both cis- and trans-configurations were focused here to unravel their conformational inversion-topomerization mechanisms. Full geometry optimizations were performed at B3LYP/6-311++G(d,p) level of theory to explicitly identify all distinguishable molecular structures, and thus explore potential energy surfaces (PES) of the complete interconversion routes for two stereoisomers of 1,3-dimethylcyclohexane and 1,4-dimethylcyclohexane. Additional quantum calculations were carried out by separately applying MP2/6-311++G(d,p), G4, and CCSD(T)/6-311++G(d,p) methods to further refine all PES’ stationary points. With respect to quantum results, the conformational analysis was conducted to gain insight into the determination, thermodynamic stabilities, and relative energies of distinct molecular geometric structures. On base of highly biased conformational equilibria, the temperature-dependent populations of stable local minima for four studied dimethylcyclohexanes were obtained by utilizing Boltzmann distribution within 300-2500 K. Moreover, two unique interconversion processes for them, including inversion and topomerization, were fully investigated, and their potential energy surfaces were illustrated with the rigorous descriptions in two or three-dimensional schemes for clarify.

scholarly journals Torsional Potential Energy Surfaces of Dinitrobenzene Isomers

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Paul M. Smith ◽  
Mario F. Borunda
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Three Dimensional ◽  
Molecular Structures ◽  
Basis Sets ◽  
Valuable Insight ◽  
Complex Molecules ◽  
Torsional Potential ◽  
Energy Surfaces

The torsional potential energy surfaces of 1,2-dinitrobenzene, 1,3-dinitrobenzene, and 1,4-dinitrobenzene were calculated using the B3LYP functional with 6-31G(d) basis sets. Three-dimensional energy surfaces were created, allowing each of the two C-N bonds to rotate through 64 positions. Dinitrobenzene was chosen for the study because each of the three different isomers has widely varying steric hindrances and bond hybridization, which affect the energy of each conformation of the isomers as the nitro functional groups rotate. The accuracy of the method is determined by comparison with previous theoretical and experimental results. The surfaces provide valuable insight into the mechanics of conjugated molecules. The computation of potential energy surfaces has powerful application in modeling molecular structures, making the determination of the lowest energy conformations of complex molecules far more computationally accessible.

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