HIGH PRESSURE CHEMISTRY, I: ULTRA RAPID RATES AT VERY HIGH PRESSURES

Chemistry at high pressure.

Chemistry involves the study of the reactions and properties of the elements and their compounds. After over two centuries of systematic chemical research, combined with the modern use of spectroscopy and diffraction methods to determine structure and valence states and detailed quantum mechanical investigations of interatomic bonding; it is now generally accepted that the fundamentals of chemi...

Predicted reentrant melting of dense hydrogen at ultra-high pressures

The phase diagram of hydrogen is one of the most important challenges in high-pressure physics and astrophysics. Especially, the melting of dense hydrogen is complicated by dimer dissociation, metallization and nuclear quantum effect of protons, which together lead to a cold melting of dense hydrogen when above 500 GPa. Nonetheless, the variation of the melting curve at higher pressures is virt...

New Methods for Investigating Superconductivity at Very High Pressures

1. – Introduction As a result of rapid developments in diamond-cell techniques, a broad range of studies of the physical and chemical properties of solids can be now conducted in situ to megabar pressures (i.e., > 100 GPa). The highest superconducting T c has been achieved by application of pressure of ∼ 30 GPa on HgBa 2 Ca 2 Cu 3 O 8+δ giving critical superconducting temperature of 164 K [3]. ...

Adsorption at High Pressures

The compositional variation of synthetic sodic amphiboles at high and ultra-high pressures

Sodic amphiboles in high pressure and ultrahigh pressure (UHP) metamorphic rocks are complex solid solutions in the system Na2O±MgO±Al2O3±SiO2± H2O (NMASH) whose compositions vary with pressure and temperature. We conducted piston-cylinder experiments at 20±30 kbar and 700±800 °C to investigate the stability and compositional variations of sodic amphiboles, based on the reaction glaucophane ˆ 2...