Rutile (TiO2) implanted with 10-keV H+ and D+ exhibits broad ir absorption bands at 3400 and 2505 cm−1, respectively. The D+ implantation also induces a sharp band at 2438 cm−1. This 2438-cm−1 band corresponds to the sharp hydroxyl absorption peak at 3277 cm−1 typically present in flame-grown rutile crystals. In addition the bombardment induces a broad absorption at 900 nm, which is attributed to delocalized electrons resulting from direct chemical reduction of the rutile by the implanted hydrogen or deuterium, and which is similar to the well-known 1500-nm free-carrier absorption in rutile heated in a reducing atmosphere. The absence of such an absorption after 10-keV He+ or Ar+ bombardment implies that reduction by preferential sputtering does not significantly contribute to this band. Evidence is adduced to support the view that the 900-nm absorption, which appears to the eye as a blue color, is associated with chemically implanted D+. Using projected ranges for 10-keV D+ and experimentally determined transition moments for O–D stretch intensities leads to a value for the oscillator strength of the ’’blue’’ band of ∠0.1. The large f value supports the assignment of the ’’blue’’ band to free-carrier absorption rather than to a d–d transition localized at a Ti3+ site.