Publication from Cole group, titled "Vibrational Behavior of Water Adsorbed on Forsterite (Mg2SiO4) Surface"
Postdoc Tingting Liu and Research Associate Siddharth Gautam from the Cole group recently published their work on water vibrational behavior on olivine's surfaces in ACS Earth and Space Chemistry. Funded by Department of Energy and the Sloan Foundation-funded Deep carbon Observatory, this work involves collaboration with scientists from Oak Ridge National Laboratory and European Spallation Source in Sweden. The Cole group has recently focused on probing the confinement effect of nanopores or mineral surfaces on the behavior of C-H-O fluids relevant to subsurface energy systems. As one of the major rock-forming minerals, olivine is very susceptible to chemical weathering involving water and CO2. Chemically adsorbed surface water plays a key role in determining the reaction pathway and kinetics. This study utilized both experimental and simulation tools to examine the interfacial dynamic behavior of water molecules on the surfaces of forsterite (magnesium end member of olivine). The results demonstrate that water vibrational behavior are strongly affected by the surrounding conditions such as water fugacity and temperature. The revealed water structure and dynamics (the related diffusion behavior was studied in Liu et al., 2018, Physical Chemistry Chemical Physics, 20, 27822-27829) on forsterite surfaces acts as the stepping stone to explore surface reactivity involving dissolution and alteration to new phases, such as serpentine, relevant to subaerial weathering and the subsurface systems. The new data also inform us on the processes controlling the uptake of water on interplanetary particles of olivine composition during early solar system formation.
