Binding Matter with Antimatter: The Covalent Positron Bond

Area of Science:

• Theoretical Chemistry
• Quantum Mechanics
• Atomic and Molecular Physics

Background:

• Positron interactions with matter are typically studied as positron attachment to stable molecules, characterized by positron affinity.
• The behavior of positrons interacting with anions, particularly hydride anions, is less understood.
• Exploring novel molecular structures involving positrons can reveal new bonding mechanisms.

Purpose of the Study:

• To investigate the theoretical energy stability of the positron hydride (e+⋅H22-) molecule.
• To analyze the nature of the bond formed between hydride anions and a positron.
• To differentiate this novel bonding from standard positron attachment phenomena.

Main Methods:

• Computational quantum chemistry methods were employed to model the e+⋅H22- system.
• Analysis of electronic and positronic density distributions was performed.
• Calculation of the binding energy, including zero-point vibrational correction, was conducted.

Main Results:

• Sufficient theoretical evidence confirms the energy stability of the e+⋅H22- molecule.
• The analysis revealed a unique positronic covalent bond between two hydride anions, mediated by the positron.
• The calculated lower limit for the binding energy is 74 kJ mol⁻¹ (0.77 eV), accounting for vibrational effects.

Conclusions:

• The formation of the e+⋅H22- molecule represents a novel type of chemical bonding involving a positron.
• This positronic covalent bond is fundamentally different from positron attachment to stable molecules.
• The study provides theoretical evidence for a stable molecule formed by anions and a positron, opening new avenues in positron chemistry research.