Bound‑electron screening mechanism for D–D fusion in palladium

Develop a specialized quantum‑chemistry model to calculate electron screening when a deuteron pair in a dideuterium complex near a palladium atom tunnels into palladium bound electron orbitals prior to fusing, and determine whether this bound‑electron screening mechanism quantitatively accounts for the large screening energies inferred from low‑energy deuteron–metal experiments at near‑zero relative energy.

Background

Standard free‑electron screening models predict screening energies around 50–150 eV for metals, yet experiments often infer 150–300 eV or higher and predict much smaller screening at zero relative energy. The authors suggest an alternative mechanism in which both deuterons in a pair tunnel into palladium bound orbitals before traversing the inter‑deuteron Coulomb barrier, potentially yielding stronger screening.

They note that evaluating this possibility requires a special‑purpose quantum chemistry computation tailored to the deuteron pair–palladium system. This conjectured mechanism has not been quantitatively assessed and could explain discrepancies between theory and experiment if validated.