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The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Third-order interactions in symmetry-adapted perturbation theory.
Konrad Patkowski1, Krzysztof Szalewicz, Bogumił Jeziorski
1Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA. patkowsk@udel.edu
The Journal of Chemical Physics
|October 25, 2006
Summary
We extended symmetry-adapted perturbation theory (SAPT) to include third-order polarization and exchange energies. This advancement accurately describes interactions, especially for dispersion-bound dimers, by accounting for electron exchange quenching.
Area of Science:
- Quantum chemistry
- Computational physics
- Intermolecular forces
Background:
- Symmetry-adapted perturbation theory (SAPT) is crucial for calculating intermolecular interaction energies.
- Previous methods neglected certain third-order contributions, limiting accuracy for some systems.
Purpose of the Study:
- To extend many-body SAPT by incorporating all third-order polarization and exchange contributions.
- To analyze the impact of electron exchange on third-order polarization energies.
- To provide accurate theoretical tools for studying molecular interactions.
Main Methods:
- Developed formulas for third-order polarization and exchange energies, including induction, dispersion, and their mixed components.
- Expressed all energy components using molecular integrals and orbital energies.
- Implemented the new methods in a general closed-shell many-electron SAPT program.
Main Results:
- Third-order polarization energy is significantly quenched by electron exchange at short ranges.
- Proposed a decomposition of third-order exchange energy to explain this quenching effect.
- Test calculations on small dimers demonstrate the accuracy of the new approach.
Conclusions:
- The inclusion of third-order effects eliminates the need for hybrid SAPT for dispersion-bound dimers.
- For strongly polar monomers, a hybrid approach may still be preferred.
- Third-order polarization effects must be included with their exact exchange counterparts for accurate results.
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