Comparisons of positron and electron binding to molecules

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry

Background:

• Understanding lepton-molecule interactions is crucial in chemical physics.
• Electron-molecule bound states are well-studied, but positron-molecule interactions are less understood.

Purpose of the Study:

• To compare positron-molecule binding with electron-molecule binding.
• To elucidate the factors governing positron binding energies.

Main Methods:

• Theoretical calculations comparing positron and electron interactions with molecules.
• Analysis of lepton density distribution and binding energies.

Main Results:

• Bound lepton density for both positrons and electrons is diffuse and located outside the molecular valence shell.
• Positron binding energies are 1-2 orders of magnitude larger than those of negative ions.
• Key factors contributing to larger positron binding energies include molecular dipole orientation and stronger lepton correlations (e.g., dipole polarizability).

Conclusions:

• Positron-molecule interactions exhibit unique characteristics compared to electron-molecule interactions.
• Molecular properties like dipole moment significantly influence positron binding.
• Further investigation into positron-molecule systems can reveal novel chemical phenomena.