The weak-correlation limits of few-electron harmonium atoms
1Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland and Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, D-01187 Dresden, Germany.
The Journal of Chemical Physics
|December 17, 2013
Summary
This study investigates electronic properties of harmonium atoms with up to four electrons. It provides new benchmarks for electron-correlation methods by deriving exact energy contributions for diverse electronic states.
Area of Science:
- Quantum Chemistry
- Atomic Physics
- Computational Physics
Background:
- Harmonium atoms are model systems for studying electron correlation.
- Accurate calculation of electronic properties is crucial for understanding atomic behavior.
Purpose of the Study:
- To investigate weak-correlation asymptotics of electronic properties in small harmonium atoms.
- To derive closed-form expressions for Hartree-Fock and correlation energies.
- To provide enhanced benchmarking data for electron-correlation methods.
Main Methods:
- Analysis of weak-correlation asymptotics.
- Derivation of closed-form expressions for energy contributions.
- Investigation of eight distinct electronic states (singlets, doublets, triplets, quartet, quintet).
Main Results:
- Exact first- and second-order contributions to Hartree-Fock and correlation energies derived.
- Analysis covers six singly determinantal and two multi-determinantal states.
- Computed energy contributions from individual spinorbitals and pairs are available.
Conclusions:
- The derived expressions and diverse states offer superior benchmarking tools.
- This work enhances the calibration of approximate electron-correlation methods.
- Detailed energy contributions increase the utility of these computational benchmarks.
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