Reinterpretation of the "Ti3+interstitial" electron-spin-resonance spectrum in rutile

A variety of rutile samples were heat treated in atmospheres of ${\mathrm{H}}_2$, ${\mathrm{H}}_2$O, and ${\mathrm{O}}_2$ according to prescriptions which theoretically and experimentally either favor or suppress H interstitial formation. The H concentration and conduction-electron concentrations in the samples were monitored optically. The "$A$" spectrum, which has been universally accepted as being due to ${\mathrm{Ti}}^{3+}$ interstitials, is found instead to be associated with H.