Ab initio study of the dolomite to dolomite-II high-pressure phase transition

Zucchini, Azzurra; Prencipe, Mauro; Belmonte, Donato; Comodi, Paola

doi:10.1127/ejm/2017/0029-2608

Cited by 20 publications

(17 citation statements)

References 55 publications

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“…Such pressure-induced softening indicates potential structural instabilities in the Dol-I structure [ Fig. 2(b) and Table 2], as predicted by recent ab initio calculations [44]. These Dol-I FIR modes are assigned to anti-translations and librations of the (CO3) 2units with respect to the Ca 2+ and Mg 2+ cations [42].…”

Section: Resultsmentioning

confidence: 52%

“…2(b)]. The aforementioned softening of both the ~120 cm -1 and the ~450 cm -1 Dol-I FIR modes is indicative of the displacive character of the Dol-I→Dol-II transition [9,44,48] .…”

Section: Gpamentioning

confidence: 97%

“…4(a)]; the back-transformation of the two dolomite polymorphs exhibits clear hysteresis, resulting (partially) from the first-order character of the Dol-II→ Dol-IIIc transition. On the other hand, the exact Dol-II→Dol-I back-transformation pressure was most likely overstepped upon decompression, as one would not expect any hysteresis effects due to the second-order nature of this transition [9,27,44,48].…”

Section: High-pressure Raman Studies At Ambient Temperature Conductedmentioning

confidence: 99%

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Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Efthimiopoulos

Germer

Jahn

et al. 2018

High Pressure Research

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We have conducted high pressure far-infrared absorbance and Raman spectroscopic investigations on a natural iron-free dolomite sample up to 40 GPa. Comparison between the present observations and literature results unraveled the effect of hydrostatic conditions on the high pressure dolomite polymorph adopted close to 40 GPa, i.e. the triclinic Dol-IIIc modification. In particular, non-hydrostatic conditions impose structural disorder at these pressures, whereas hydrostatic conditions allow the detection of an ordered Dol-IIIc vibrational response. Hence, hydrostatic conditions appear to be a key ingredient for modeling carbon subduction at lower mantle conditions. Our complementary first-principles calculations verified the far-infrared vibrational response of the ambient-and high-pressure dolomite phases.

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Section: Resultsmentioning

confidence: 52%

“…2(b)]. The aforementioned softening of both the ~120 cm -1 and the ~450 cm -1 Dol-I FIR modes is indicative of the displacive character of the Dol-I→Dol-II transition [9,44,48] .…”

Section: Gpamentioning

confidence: 97%

Section: High-pressure Raman Studies At Ambient Temperature Conductedmentioning

confidence: 99%

See 1 more Smart Citation

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Efthimiopoulos

Germer

Jahn

et al. 2018

High Pressure Research

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“…Some studies have been carried out on phase relations of binary carbonate solid solutions [13][14][15]. Furthermore, many works focus on the computational chemistry of dolomite: simulation of defects and phase stabilities as a function of temperature and pressure were carried out [16][17][18][19]. In particular, Zucchini et al [16] performed ab initio calculations at the athermal limit (T = 0 K) to study the effect of cation order/disorder on the stability of dolomite.…”

Section: Introductionmentioning

confidence: 99%

(10.4) Face of Ordered and Disordered Dolomite, MgCa(CO3)2: A Computational Study to Reveal the Growth Mechanism

Bruno

Bittarello

2018

Minerals

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In this study, the stability of the (10.4) face of dolomite was systematically investigated. The surface energies at 0 K of the different (10.4) surfaces resulting from the cut of both ordered and disordered bulk structures were determined and compared, to establish how different atomic configurations (surface terminations) can affect the stability of the investigated face. To study the thermodynamic behavior of a surface, a 2D periodic slab model and the ab initio CRYSTAL code were adopted. The surface energies of the (10.4) faces of calcite and magnesite were also calculated in order to compare them with those of the different terminations of the (10.4) face of dolomite. Our calculations showed that the bulk of the dolomite crystal must have an ordered structure to reach the minimum of the energy, whereas the (10.4) surface is more stable when its structure is disordered. A growth model of the (10.4) face has been proposed: the peculiarity of this model consists in the existence of some disordered layers forming at the interface crystal/solution, which arrange in an ordered structure once covered by others disordered layers resulting by the spiral steps propagation.

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“…Entropy term is frequently neglected (especially if space group preserves after phase transition), supposing to have a small impact on Gibbs energy, while enthalpy can be calculated relatively easy [61,67,80,81,83]. Nevertheless, a lack of entropy calculations can lead to significant mistakes in the prediction of phase stability, which was shown for many inorganic materials [84,85]. The introduction of thermal effects in phase stability (DFT-QHA) increases computational costs drastically, but phonon effects are crucial to define accurate thermodynamic properties and Gibbs energies [86].…”

Section: Dft Methodsmentioning

confidence: 99%

A Short Review of Current Computational Concepts for High-Pressure Phase Transition Studies in Molecular Crystals

Rychkov

2020

Crystals

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High-pressure chemistry of organic compounds is a hot topic of modern chemistry. In this work, basic computational concepts for high-pressure phase transition studies in molecular crystals are described, showing their advantages and disadvantages. The interconnection of experimental and computational methods is highlighted, showing the importance of energy calculations in this field. Based on our deep understanding of methods’ limitations, we suggested the most convenient scheme for the computational study of high-pressure crystal structure changes. Finally, challenges and possible ways for progress in high-pressure phase transitions research of organic compounds are briefly discussed.

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Ab initio study of the dolomite to dolomite-II high-pressure phase transition

Abstract: 4Keywords 5

Cited by 20 publications

References 55 publications

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

(10.4) Face of Ordered and Disordered Dolomite, MgCa(CO3)2: A Computational Study to Reveal the Growth Mechanism

A Short Review of Current Computational Concepts for High-Pressure Phase Transition Studies in Molecular Crystals

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