Analysis of electron-positron wavefunctions in the nuclear-electronic orbital framework

Area of Science:

• Quantum Chemistry
• Computational Physics
• Positron Annihilation Studies

Background:

• Positronic systems are crucial for understanding antimatter interactions.
• Accurate prediction of electron-positron contact densities is vital for annihilation studies.
• Existing methods may lack efficiency or accuracy for complex positronic systems.

Purpose of the Study:

• To extend and apply the nuclear-electronic orbital explicitly correlated Hartree-Fock (NEO-XCHF) approach to positronic systems.
• To evaluate the accuracy and efficiency of NEO-XCHF for predicting annihilation properties.
• To compare NEO-XCHF with the non-correlated NEO-HF method.

Main Methods:

• Utilized molecular orbital techniques with Gaussian basis sets for electrons and positrons.
• Incorporated electron-positron correlation using explicitly correlated Gaussian-type geminal functions.
• Developed an efficient strategy to minimize variational parameters in NEO-XCHF calculations.

Main Results:

• NEO-XCHF provided qualitative to semi-quantitative results for annihilation rates and densities at low computational cost.
• The NEO-HF method showed system-dependent reliability for predicting annihilation sites.
• NEO-XCHF proved to be a computationally practical and reliable method for determining annihilation locations.

Conclusions:

• The NEO-XCHF method is a valuable tool for studying electron-positron interactions and annihilation.
• Explicitly treating electron-positron correlation is essential for accurate predictions in many positronic systems.
• NEO-XCHF offers a balance of accuracy and computational efficiency for positronic system research.