Prof. Dr. DANIEL R. NEUVILLE
Senior Research Director
IPGP – CNRS / Paris Institute of Earth Physics, FR
Bio
Daniel R. Neuville is a senior Research director at CNRS-IPGP. In 1992, he obtained his PhD in Geochemistry (University Paris Diderot, IPGP). Since 2014; he is the head of the Geomatériaux group of IPGP. Since 2013, he is in charge of the Master of Geochemistry, geomaterial, geobiology and environement program of Université de Paris Cité. He was secretary of the French Mineralogical and Cristallography Society, between 1994 and 2009. He has organized several international workshops and schools and convened many sessions at international meetings, such as EGU, Goldschmidt, IMA, AGU, GOMD. In 1999, he obtained the Jean Rose Price by the French Association of Science and in 2007-2008, he was Joubin-James Invited professor at University of Toronto. He was elected fellow of the American Mineralogical society in 2018 and he received the Otto Schott research Award from Ernst Abbe Fund in 2022.
Since 2007, he is Editor of the amorphous material issues of the American Mineralogist; Guest Editor for Elements, vol. 6 (2010), "Thermodynamics: the oldest branch of earth science", and vol. 16 (2020) "The redox engine of the Earth" and Review in Mineralogy and Geochemistry, vol. 78 (2014) "Spectroscopic methods in Mineralogy and Material Sciences", and vol. 87 (2022) "Geological Melts" and for American Geophysical Union Monography on "Magma Redox Geochemistry"(2021).
In 2012, he was elected president of the French glass society (USTV), and relected in 2015 and 2018. Since 2013, he is elected Chair of the TC3 Committee of the structure and properties of glass of the International Commision on Glass. He was the elected chair of the commission of Mineral Physics of the International Mineralogical Association (2014-2022).
He has published more than 210 international articles, and given more than 400 presentations at international congresses, more than 60 invited conferences.
Presentation
How and Why Investigate the Structural Role of Elements in Glass and Liquid?
Alkali and alkaline earth can be a network modifier or a charge compensator of AlO4- in aluminosilicate glasses and melts. As a function of its role, density, molar volume, viscosity, liquidus and glass transition temperature and more generally, macroscopic properties can change significantly. But how evaluate or prove this change of role? Recently, Helhen and Neuville (2014) have shown by comparing Raman in VV and VH polarization, that a new band appears in the VH Raman spectra when the role of Ca changes from charge compensator to network modifier. Furthermore, we have shown in the XANES spectra at the Ca K-edge, an important change in the Ca pre-edge peaks as a function of this same change of role (Cicconi et al., 2015).
Application to redox processes: in the case of an Fe2+/Fe3+ silicate, like window glass or natural lava, Fe3+ can be consider playing same role than Al3+ following result on viscosity (Dingwell, 1991). By looking Ca pre-edge peaks, in window glasses, is possible to follow a change in the role of Ca as a function of redox, similar at those observe with or without Al. This variation of the role of Ca is associated with the need of Fe3+ to be compensated, and it proved that Fe3+ acts in the network former as Al3+. Furthermore, the large variations of the oxygen distribution around Ca could explain the large variations of the redox mechanisms in silicate melts.
Application to nucleation processes: Ca environment can be a key to understand nucleation process. Indeed, the nucleation process is very difficult to follow and needs highly sensitive tools. In fact, Ca is expected to move at lower temperatures than atoms involved in the glass network, in agreement with observation on relaxation processes (Gruener et al. 2001). As a consequence, Ca environment should be quickly modified in case of nucleation. Neuville et al. (2008) observed that, in a diopside composition, Ca pre-edge peak was modified and associated it with a change of Ca site from an “amorphous” one, to a “pre-nucleus” one. The quantitative approach of the Ca pre-edge XANES spectra, presented here, has the sensitivity required to further study nucleation.
To conclude, by looking the role of alkaline earth element in glass and melts, it is possible have a better knowledge of the structure of glass and melts, but also to better understand redox and nucleation processes.