The Science & Technology
of Glass
Cambridge - Monday 4th to
Wednesday 6th September 2017

Gavin Mountjoy
<[email protected]>

article posted 07 August 2017

Dr Gavin Mountjoy is a Reader in Condensed Matter Physics at the University of Kent. During his research career he has worked at the Cavendish Laboratory, University of Cambridge, the Centre for Solid State Science, Arizona State University, and the Functional Materials Group, University of Cagliari. Gavin is a long-standing member of the School of Physical Sciences, University of Kent, including previously holding roles of Director of Teaching and Deputy Head of School. His research involves structural characterization techniques of electron microscopy, x-ray spectroscopy, x-ray and neutron scattering, and molecular dynamics modelling. He is primarily interested in applying these techniques to nanocomposites and amorphous solids, especially oxide glasses, with applications in optics, as energy materials, and as biomaterials.

Molecular dynamics of oxide glasses as a complement to conceptual and experimental techniques
Gavin Mountjoy
School of Physical Sciences, University of Kent, Canterbury CT2 7NH, U.K.

This talk will discuss the classical molecular dynamics technique for building structural models of oxide glasses, with many examples from silicate and phosphate glass systems. One of the most valued results from molecular dynamics is a visual representation of glass structure which is an essential complement to conceptual models. Comparison of molecular dynamics models with the important modified random network conceptual model shows the latter omits some subtleties related to bridging oxygens, free oxygens, and modifier cation channels. Due to the absence of long range order, pair distribution functions (PDFs) play a fundamental role in describing glass structures. Such PDFs are another greatly valued output from molecular dynamics which provides a strong complement to x-ray and neutron diffraction. (Conversely, diffraction is important for validating molecular dynamics.) A further benefit of molecular dynamics is the possibility to study changes in atomic structure with composition in greater detail than might be possible using experimental techniques. This talk will illustrate use of complementary molecular dynamics and experimental techniques to provide insights to structural mechanisms related to doping, phase separation, and chemical durability.

Figure: (left) molecular dynamics model of calcium metaphosphate glass and (right) representation in terms of phosphate network backbone and calcium channels.