Chapter 2. VIBRATIONAL SPECTROSCOPY in the MINERAL SCIENCES

McMillan, Paul F.

doi:10.1515/9781501508868-004

Cited by 23 publications

(22 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, if we consider the difference between calculated and observed values to be solely due to anharmonicity, the SP-GGA results predict an anharmonicity of approximately 8% whereas the SP-GGA+U method predicts approximately 3% anharmonicity. The latter value is more consistent with previous DFT results comparing observed and predicted vibrational frequency anharmonicities [37], so we believe the SP-GGA+U method is more accurate.…”

Section: Resultssupporting

confidence: 91%

Periodic density functional theory calculations of bulk and the (010) surface of goethite

2008

View full text Add to dashboard Cite

BackgroundGoethite is a common and reactive mineral in the environment. The transport of contaminants and anaerobic respiration of microbes are significantly affected by adsorption and reduction reactions involving goethite. An understanding of the mineral-water interface of goethite is critical for determining the molecular-scale mechanisms of adsorption and reduction reactions. In this study, periodic density functional theory (DFT) calculations were performed on the mineral goethite and its (010) surface, using the Vienna Ab Initio Simulation Package (VASP).ResultsCalculations of the bulk mineral structure accurately reproduced the observed crystal structure and vibrational frequencies, suggesting that this computational methodology was suitable for modeling the goethite-water interface. Energy-minimized structures of bare, hydrated (one H2O layer) and solvated (three H2O layers) (010) surfaces were calculated for 1 × 1 and 3 × 3 unit cell slabs. A good correlation between the calculated and observed vibrational frequencies was found for the 1 × 1 solvated surface. However, differences between the 1 × 1 and 3 × 3 slab calculations indicated that larger models may be necessary to simulate the relaxation of water at the interface. Comparison of two hydrated surfaces with molecularly and dissociatively adsorbed H2O showed a significantly lower potential energy for the former.ConclusionSurface Fe-O and (Fe)O-H bond lengths are reported that may be useful in surface complexation models (SCM) of the goethite (010) surface. These bond lengths were found to change significantly as a function of solvation (i.e., addition of two extra H2O layers above the surface), indicating that this parameter should be carefully considered in future SCM studies of metal oxide-water interfaces.

show abstract

Section: Resultssupporting

confidence: 91%

Periodic density functional theory calculations of bulk and the (010) surface of goethite

2008

View full text Add to dashboard Cite

show abstract

“…Detailed peak assignments of the polarized Raman spectrum of forsterite can be found in Ishii (1978); Price et al (1987); Piriou and McMillan (1983) and McMillan (1985), and those of olivine in general are given by Chopelas (1991). Olivine has 84 normal vibrational modes; among which, 81 are optic modes and 36 are Raman-active modes (Ishii, 1978;Hofmeister, 1987).…”

Section: Olivine Samples and The Raman Spectrum Of Olivinementioning

confidence: 99%

Extracting olivine (Fo–Fa) compositions from Raman spectral peak positions

Kuebler¹,

Jolliff²,

Wang³

et al. 2006

Geochimica et Cosmochimica Acta

229

258

View full text Add to dashboard Cite

“…(Wilson et al, 1955;Decius and Hexter, 1977;Nakamoto, 1978;McMillan, 1985;Schrader, 1994). Within polyatomic molecules and solids, the potential energy function forms a multidimensional surface (E()), where represents the various interatomic displacement coordinates, that are commonly expressed as bond-stretching, angle-bending motions, etc.…”

Section: Molecular Vibrationsmentioning

confidence: 99%

“…(a) In a diatomic molecule, the two atoms can be approximated by point masses (m 1 , m 2 ) and the bonding between them as a classical spring with force constant f. The separation between the atoms is r. (b) Molecular vibrations are usefully treated in center-of-mass coordinates, using the reduced mass (m Ã ¼ m 1 m 2 /(m 1 þ m 2 )). McMillan, 1985;McMillan and Hofmeister, 1988;Schrader, 1994). (c) That model of a diatomic vibration is readily extended to that of a monatomic chain, to provide a useful approach for understanding the vibrations of crystals.…”

Section: Molecular Vibrationsmentioning

confidence: 99%

“…The diatomic vibration then corresponds to that of a single particle with reduced mass m Ã , held between fixed walls by equal springs, each with force constant f/2. The symmetry analysis is readily extended to crystalline minerals, where the point group of the unit cell is used instead of that of the finite molecule (Fateley et al, 1972;Farmer, 1974;Decius and Hexter, 1977;McMillan, 1985). The lattice repeat distance is a.…”

Section: Molecular Vibrationsmentioning

confidence: 99%

See 1 more Smart Citation