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Slimmer Geminals For Accurate F12 Electronic Structure Models
Samuel R Powell1, Kshitijkumar A Surjuse1, Bimal Gaudel1
1Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24060, United States.
Journal of Chemical Theory and Computation
|September 10, 2025
Summary
New geminal parameters improve high-order F12 methods by reducing basis set incompleteness errors (BSIEs). This optimization enhances correlation energies in coupled-cluster F12 calculations, particularly for specialized basis sets.
Area of Science:
- Quantum Chemistry
- Computational Chemistry
- Theoretical Chemistry
Background:
- Slater-type geminal length scales are crucial for F12 methods.
- Existing parameters optimized for second-order Møller-Plesset F12 are unsuitable for higher-order F12 methods.
Purpose of the Study:
- To develop and report new geminal parameters for higher-order F12 methods.
- To reduce basis set incompleteness errors (BSIEs) in correlated energy calculations.
Main Methods:
- Reoptimization of geminal parameters for F12 methods.
- Application in coupled-cluster singles and doubles F12 (CCSD(2)-F12) calculations.
- Comparison with conventional and F12-optimized basis sets (e.g., cc-pVXZ-F12).
Main Results:
- New parameters significantly reduce BSIEs for absolute correlation energies.
- The improvement is more pronounced with larger cardinal numbers in basis sets.
- Substantial reductions in BSIEs for relative energies, especially atomization energies and ionization potentials, were observed.
Conclusions:
- The reoptimized geminal parameters are recommended for high-order F12 methods.
- This includes coupled-cluster F12 and transcorrelated F12 methods.
- The findings enhance the accuracy of quantum chemical calculations using F12 techniques.
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