Infrared intensity and charge transfer in hydrogen dimers

Direct evaluation of the dipole derivative μ′ for overlapping H2 dimers is consistent with the vibron oscillator strength of ≈ 10−5 at the 150 GPa transition of dense hydrogen. The angular anisotropy of μ′ follows closely the σ−σ∗ overlap for charge transfer (CT) between closed-shell H2 molecules. We relate electron-vibron coupling above 150 GPa to CT models for ion-radical solids and conjugated polymers.