Computational Assignment of Tantalum-related Strong Absorption Peaks in the Infrared Spectrum of Potassium Heptafluorotantalate.

Tantalum (Ta) is a valuable and rare metal that is extensively used in the production of implant materials and high-performance capacitors. However, a convenient and effective method for the separation of Ta from other compounds has yet to be developed. On the basis of first-principle density functional theory (DFT), we simulated the vibrational spectrum of potassium heptafluorotantalate (K 2 TaF 7 ). By performing a dynamics analysis of vibrational modes, we assigned peaks in infrared (IR) absorption and Raman scattering spectra to their corresponding vibrations. We focused on the strong IR absorption peaks of Ta-related vibrational modes in K 2 TaF 7 and concluded that three observed IR absorption peaks, at 285, 315, and 530 cm -1 , are good candidates. Provided with high power radiation at these three frequencies (at about 8.55, 9.45, and 15.9 THz), the good efficiency of photon-phonon resonance absorption will facilitate Ta separation from a compound.