IJCEA 2025 Vol.16(1): 41-47
doi: 10.18178/ijcea.2025.16.1.41-47
A Novel Hybrid Post-Hartree-Fock and Monte Carlo Algorithm for the Characterization of Conformational Isomers in Acyclic Alkanes
Ram Sivaraman*, Rishab Ghosh, Jayden Lim, Shashank Kondaveeti, and Larry McMahan
Aspiring Scholars Directed Research Program, Fremont, United States of America
Email: 2ram.sivaraman@gmail.com (R.S.); Rishabghosh485@gmail.com (R.G.); jaydenclim@gmail.com (J.L.); kshashank61@gmail.com (S.K.); larry.mcmahan@asdrp.org (L.M.)
*Corresponding author
Manuscript received September 15, 2024; accepted January 17, 2025; published May 23, 2025
Abstract—Determining the molecular Hamiltonian proves to be an essential tool in understanding a molecule’s properties, including energy changes in reactions and molecular stability. Traditional self-consistent field methods such as Hartree-Fock have been long-standing approaches for approximating the Schrodinger equation to help find molecular Hamiltonians. However, their limitation in handling perturbation energies has led to the development of Post-Hartree-Fock methods, including the Møller–Plesset perturbation theory. This research aims to introduce a novel method for the analysis of conformational isomers of acyclic alkanes utilizing the Møller–Plesset perturbation theory. Specifically, the geometric and Hamiltonian characteristics of conformers are analyzed. Conformers are computationally generated, and their molecular Hamiltonians are evaluated. The method uses a single molecular structure as input and combines Monte Carlo simulations with classical geometric clustering to generate possible conformers. Ethane, propane and isobutane are used for the analysis of this methodology. The molecular geometries are evaluated using the Computational Chemistry Comparison and Benchmark Database (CCCBDB) with the MP2/cc-pVDZ basis set. Results from this research showcase that narrower angle bounds lead to more plausible and stable structures, primarily indicated by the low variability in energy values.
Keywords—Hartree-Fock, Post-Hartree-Fock, perturbation theory, Møller-Plesset, conformational isomers, Schrödinger’s equation, Monte Carlo
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Cite: Ram Sivaraman, Rishab Ghosh, Jayden Lim, Shashank Kondaveeti, and Larry McMahan, "A Novel Hybrid Post-Hartree-Fock and Monte Carlo Algorithm for the Characterization of Conformational Isomers in Acyclic Alkanes," International Journal of Chemical Engineering and Applications vol. 16, no. 1, pp. 41-47, 2025.
