*Any student or postdoc that has been published as a first author in a paper which relied on COMPRES facilities can email the COMPRES student/postdoc represenatives at firstname.lastname@example.org to have a student highlight added to the page. Please include the title, a short (1-2 sentence) description, a figure/image and the DOI.
High-pressure behavior of the polymorphs FeOOH
Mary Reagan (PhD candidate at Stanford) and coauthors recently published a study in American Mineralogist which compares the high-pressure structural and electronic behavior of α-, β-, and γ-FeOOH. These phases were studied in-situ using a combination of synchrotron X-ray diffraction and X-ray emission spectroscopy. Gaining understanding OH- and Fe3+ bearing phases can shed light on our understanding of the water content and oxidation state of the mantle.
The ammonium ion in a silicate under compression: Infrared spectroscoy and powder x-ray diffraction of NH4AlSi3O8 —buddingtonite to 30 GPa
Cara Vennari (PhD candidate at UC Santa Cruz) and coauthors recently published a study in Physics and Chemistry of Minerals that investigates the ammonium-feldspar ‘buddingtonite’ using infrared spectroscopy and synchrotron-based powder X-Ray diffraction at high pressure to provide insight into nitrogen subduction into the Earth via ammonium hosted in silicates. They probed the bonding between the ammonium and aluminosilicate framework under pressure (in particular, hydrogen bonding), and the affect of the ammonium on the elasticity and behavior of the aluminosilicate framework as a function of pressure.