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Updated: May 21, 2026
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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Hierarchical Truncations for Many-Body Expansion Potentials
Bryce M Westheimer1,2,3,4, Mark S Gordon3,4, Emilie B Guidez1,2
1Department of Chemistry, University of Colorado, Denver, Colorado 80217, United States.
Journal of Chemical Theory and Computation
|May 20, 2026
Summary
A new hierarchical many-body expansion (HMBE) method efficiently truncates high-order terms in large molecular systems. This approach offers accurate calculations for complex structures like proteins with reduced computational cost.
Area of Science:
- Computational chemistry
- Theoretical chemistry
- Molecular modeling
Background:
- The many-body expansion (MBE) is a powerful method for calculating properties of large molecular systems.
- However, computing high-order terms in MBE can be computationally expensive.
- Accurate and efficient methods are needed to model increasingly complex systems.
Purpose of the Study:
- To introduce a novel hierarchical many-body expansion (HMBE) approach.
- To develop a strategy for truncating high-order terms in MBE more efficiently.
- To enable accurate modeling of very large molecular systems.
Main Methods:
- The proposed hierarchical many-body expansion (HMBE) method partitions systems into multitier fragments.
- Numerical tests were performed on (H2O)64 structures.
- The HMBE scheme allows for optional inclusion of "Schengen terms" at fragment interfaces to enhance accuracy.
Main Results:
- HMBE demonstrated satisfactory relative energies and binding energies for (H2O)64 clusters compared to full calculations.
- Significantly fewer high-order terms were computed using HMBE than conventional MBE.
- The accuracy of HMBE can be further improved with "Schengen terms".
Conclusions:
- The hierarchical many-body expansion (HMBE) scheme is a promising framework for modeling very large molecular systems.
- HMBE offers a computationally efficient and accurate alternative to conventional MBE.
- This method is particularly suitable for systems with inherent hierarchical structures, such as proteins.
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