Electronic interactions in metal-hydrogen solid solutions: ${\mathrm{ScH}}_{\mathrm{x}}$, ${\mathrm{YH}}_{\mathrm{x}}$, and ${\mathrm{V}}_{0.75}$${\mathrm{Nb}}_{0.25}$${\mathrm{H}}_{\mathrm{x}}$

The electronic interactions of hydrogen in a host metal lattice have been studied with synchrotron-radiation photoemission for low-x solid solution phases of ${\mathrm{ScH}}_{\mathrm{x}}$, ${\mathrm{YH}}_{\mathrm{x}}$, and ${\mathrm{V}}_{0.75}$ ${\mathrm{Nb}}_{0.25}$ ${\mathrm{H}}_{\mathrm{x}}$ for 0.15≤x≤0.25. For each system, a single well-defined hydrogen-induced feature is observed 5 eV below the Fermi level due to the local interaction of H with bonding metal-derived states, in agreement with linear combination of atomic orbitals save no evidence for hydride formation induced by cleaving the α-phase hydride samples.