Open AccessAnalysis of the specific vibration modes of goethite (α-FeOOH) by terahertz spectroscopy and calculations of the vibration frequencies of a single molecule using density functional theory
Author(s) -
Ryô Hasegawa,
Takashi Kimura,
Tadao Tanabe,
Katsuhiro Nishihara,
Akira Taniyama,
Yutaka Oyama
Publication year - 2018
Publication title -
journal of biomedical graphics and computing
Language(s) - English
Resource type - Journals
eISSN - 1925-4016
pISSN - 1925-4008
DOI - 10.5430/jbgc.v8n1p29
Subject(s) - terahertz radiation , materials science , galvanization , spectroscopy , vibration , fourier transform infrared spectroscopy , infrared , goethite , corrosion , metal , infrared spectroscopy , crystal (programming language) , optics , optoelectronics , metallurgy , composite material , chemistry , physics , acoustics , organic chemistry , layer (electronics) , quantum mechanics , adsorption , computer science , programming language
Steel sheet with an insulator to prevent corrosion is used for various purposes including in building and car manufacture. Terahertz waves, for which insulators are highly permeable and metal surfaces are highly reflective, have been studied in order to establish a new inspection technology for these steel plates. In our previous research, spectroscopic measurements in the 1.0-4.0 THz range, generated by a GaP crystal, were carried out in order to collect information on the infrared activity of the metal corrosion products formed on Zn-Al hot-dip galvanized steel sheet. In the previous work, the infrared activity of Fe-based corrosion products was not examined. To examine these products, we conducted THz spectroscopy on goethite (α-FeOOH) in the range from 8.4 to 11.0 THz, generated by a GaSe crystal. The results of Attenuated Total Reflectance (ATR) FTIR spectral measurements and molecular vibration calculations were analyzed, on the basis of which the natural vibration modes of α-FeOOH in the THz frequency range were assigned.