The infrared spectrum of a putative metal hydride complex exhibited an intense feature at 1910 cm-1 that was thought to be due to iridium-hydrogen stretching (Ir-1H). An isotopic substitution experiment aimed at confirming the origin of this spectral feature was conducted in which deuterium gas was used in place of hydrogen gas to synthesize the iridium complex. What is the expected wavenumber of the corresponding iridium-deuterium (Ir-2H) stretching vibration?