Next Article in Journal
A Review of Flotation Separation of Mg Carbonates (Dolomite and Magnesite)
Next Article in Special Issue
Combined DFT and XPS Investigation of Cysteine Adsorption on the Pyrite (1 0 0) Surface
Previous Article in Journal
Evaluation of Viscosity, Strength and Microstructural Properties of Cemented Tailings Backfill
Previous Article in Special Issue
(10.4) Face of Ordered and Disordered Dolomite, MgCa(CO3)2: A Computational Study to Reveal the Growth Mechanism
Open AccessArticle

Multiscale Computational Simulation of Amorphous Silicates’ Structural, Dielectric, and Vibrational Spectroscopic Properties

Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Republic of Catalonia, Spain
Isis Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0QX, UK
Institute of Chemical Research of Catalonia, ICIQ, and The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain
Author to whom correspondence should be addressed.
Minerals 2018, 8(8), 353;
Received: 25 June 2018 / Revised: 26 July 2018 / Accepted: 7 August 2018 / Published: 15 August 2018
(This article belongs to the Special Issue Computational Methods in Mineralogy and Geochemistry)
Silicates are among the most abundant and important inorganic materials, not only in the Earth’s crust, but also in the interstellar medium in the form of micro/nanoparticles or embedded in the matrices of comets, meteorites, and other asteroidal bodies. Although the crystalline phases of silicates are indeed present in nature, amorphous forms are also highly abundant. Here, we report a theoretical investigation of the structural, dielectric, and vibrational properties of the amorphous bulk for forsterite (Mg2SiO4) as a silicate test case by a combined approach of classical molecular dynamics (MD) simulations for structure evolution and periodic quantum mechanical Density Functional Theory (DFT) calculations for electronic structure analysis. Using classical MD based on an empirical partial charge rigid ionic model within a melt-quenching scheme at different temperatures performed with the GULP 4.0 code, amorphous bulk structures for Mg2SiO4 were generated using the crystalline phase as the initial guess. This has been done for bulk structures with three different unit cell sizes, adopting a super-cell approach; that is, 1 × 1 × 2, 2 × 1 × 2, and 2 × 2 × 2. The radial distribution functions indicated a good degree of amorphization of the structures. Periodic B3LYP-geometry optimizations performed with the CRYSTAL14 code on the generated amorphous systems were used to analyze their structure; to calculate their high-frequency dielectric constants (ε); and to simulate their IR, Raman, and reflectance spectra, which were compared with the experimental and theoretical crystalline Mg2SiO4. The most significant changes of the physicochemical properties of the amorphous systems compared to the crystalline ones are presented and discussed (e.g., larger deviations in the bond distances and angles, broadening of the IR bands, etc.), which are consistent with their disordered nature. It is also shown that by increasing the unit cell size, the bulk structures present a larger degree of amorphization. View Full-Text
Keywords: DFT; periodic simulations; amorphous minerals; physicochemical properties; super-cell DFT; periodic simulations; amorphous minerals; physicochemical properties; super-cell
Show Figures

Graphical abstract

MDPI and ACS Style

Martínez-González, J.Á.; Navarro-Ruiz, J.; Rimola, A. Multiscale Computational Simulation of Amorphous Silicates’ Structural, Dielectric, and Vibrational Spectroscopic Properties. Minerals 2018, 8, 353.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Back to TopTop