Lawrence Livermore National Laboratory (LLNL) scientists recently collected high-precision thermodynamic data on warm dense nitrogen under severe conditions that could direct towards a better awareness of the insides of celestial objects such as white dwarfs and exoplanets.
The team included researchers from the University of California, Berkeley, and the University of Rochester. They utilized an advanced technique that blends pre-compression in a diamond anvil cell and laser-driven shock compression at the Omega Laser Facility at the University of Rochester.
Prior studies with this effective technique demonstrated experimental proof for superionic water ice and helium rain in gas-giant planets. In recent research, the team performed shock experiments on precompressed molecular nitrogen fluid up to 800 GPa of pressure.
They identified clear impressions for the completion of molecular dissociation near 70–100 GPa and 5–10 kK and the advent of ionization for the outermost electrons above 400 GPa and 50 kK.
“It is very exciting that we can use shock waves to break these molecules and understand how pressure and density induce changes in chemical bonding,” announced LLNL physicist Yong-Jae Kim, lead author of a paper appearing in Physical Review Letters. “Studying how to break nitrogen molecules and how to free up electrons is a great test for the most advanced computer simulations and theoretical modeling.”