Well done Dean for our 2nd RSI of the year!

The employment of high-pressure gases as a pressure-transmitting medium, sample, or reactant for diamond anvil cell experiments is widespread. As a pressure transmitter, high-pressure gases are crucial to forming quasi-hydrostatic compression atmospheres for samples inside the uniaxially driven cell. We describe an optical design for forming high-resolution images of the gasket and sample chamber of the diamond anvil cell under high gas pressures in a gas loading apparatus. Our design is simple, is of low-cost, and may be easily adapted to suit gas loading apparatus of any design, as well as other common hard-to-reach environments in diamond anvil cell experiments, i.e., those with large stand-off distances, such as cryostats




Congrats to Dylan for a great first paper!

The pyrite mineral  was recently shown to undergo a giant pressure-induced volume collapse at  12 GPa, via a disordered intermediate phase. The high pressure arsenopyrite phase is stabilised by metal-metal bonding, a mechanism now shown to be ubiquitous for  chalcogenides. Here we report a spectroscopic investigation of this transition up to pressures of 22 GPa. Using XANES we show that the transition does not involve a change in oxidation state, consistent with the arsenopyrite crystal structure proposed at high pressure. Notably, the XANES spectrum is almost identical in the pressure-induced disordered phase, and after crystallisation induced by laser-heating. The former is therefore a ‘valence bond glass’, and is likely disordered due to kinetic hindrance of the phase transition. We also detect electronic changes in the compressed pyrite phase, and this is confirmed by Raman scattering which shows that the disulphide vibrations in the pyrite phase saturate before the volume collapse. Together with detailed DFT calculations, these results indicate that electronic changes precede valence bond formation between the cations.




Nobel Prize in Physics 2018

The Nobel Prize in Physics 2018 was awarded "for groundbreaking inventions in the field of laser physics" with one half to Arthur Ashkin "for the optical tweezers and their application to biological systems", the other half jointly to Gérard Mourou and Donna Strickland "for their method of generating high-intensity, ultra-short optical pulses" ."




Well done Christian for his recent publication in Inorganic Chemistry

La2Sn2O7 is investigated under extreme conditions via laser heating in a diamond anvil cell with X-ray diffraction and Raman spectroscopy. DFT simulations support the experimental findings. A new ground state at 70 GPa that is recoverable to ambient conditions is revealed. The final state of the system is highly pathway dependent due to the covalent nature of the Sn−O bonding. Related La2Tc2O7 is simulated to determine the likelihood it has behavior analogous to that of La2Sn2O7