Abstract
Vibrational properties of diaspore, α-AlOOH, have been re-investigated using room-temperature single-crystal Raman spectroscopy and low-temperature powder infrared (IR) transmission spectroscopy. First-principles harmonic calculations based on density functional theory provide a convincing assignment of the major Raman peaks and infrared absorption bands. The large width of the Raman band related to OH stretching modes is ascribed to mode-mode anharmonic coupling due to medium-strength H-bonding. Additional broadening in the powder IR spectrum arises from depolarization effects in powder particles. The temperature dependence of the IR spectrum provides a further insight into the anharmonic properties of diaspore. Based on their frequency and temperature behavior, narrow absorption features at ~2,000 cm -1 and anti-resonance at ~2,966 cm -1 in the IR spectrum are interpreted as overtones of fundamental bending bands.
Original language | English (US) |
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Pages (from-to) | 93-102 |
Number of pages | 10 |
Journal | Physics and Chemistry of Minerals |
Volume | 39 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2012 |
All Science Journal Classification (ASJC) codes
- General Materials Science
- Geochemistry and Petrology