Diamond formation kinetics in shock-compressed C─H─O samples recorded by small-angle x-ray scattering and x-ray diffraction

Abstract

Extreme conditions inside ice giants such as Uranus and Neptune can result in peculiar chemistry and structural transitions, e.g., the precipitation of diamonds or superionic water, as so far experimentally observed only for pure C─H and H 2 O systems, respectively. Here, we investigate a stoichiometric mixture of C and H 2 O by shock-compressing polyethylene terephthalate (PET) plastics and performing in situ x-ray probing. We observe diamond formation at pressures between 72 ± 7 and 125 ± 13 GPa at temperatures ranging from ~3500 to ~6000 K. Combining x-ray diffraction and small-angle x-ray scattering, we access the kinetics of this exotic reaction. The observed demixing of C and H 2 O suggests that diamond precipitation inside the ice giants is enhanced by oxygen, which can lead to isolated water and thus the formation of superionic structures relevant to the planets’ magnetic fields. Moreover, our measurements indicate a way of producing nanodiamonds by simple laser-driven shock compression of cheap PET plastics.

A review on photochemical effects of common plastics and their related applications

“…This work not only advances the understanding of changes in the internal changes of ice giant planets, but also promoted a new process for producing miniature diamonds. 366 Besides, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the coronavirus disease-19 (COVID-19) pandemic spread all over the world, which has led to a huge consumption of masks and personal protective materials worldwide. Some poor quality protective equipment not only cannot be used to resist the invasion of the virus, but even aggravate the problem of environmental pollution, especially microplastic pollution and nanoplastic pollution.…”

Linear-response time-dependent density functional theory approach to warm dense matter with adiabatic exchange--correlation kernels

“…WDM is generated in experiments e.g. by laser heating and/or shock compression at facilities such as the National Ignition Facility (NIF) [1,2,8], the European X-ray Free-Electron Laser (XFEL) [9], and the Linac coherent light source (LCLS) at SLAC [10]. In nature, WDM exists in the interior of white dwarfs [11,12] and giant planets [13,14], and in the outer layer of neutron stars [15].…”

Non-empirical Mixing Coefficient for Hybrid XC Functionals from Analysis of the XC Kernel

“… 8 Additionally, hybrid XC functionals enable thermal XC effects 9 , 10 to be treated more accurately than usual ground-state functionals due to the inherent use of thermally smeared occupation numbers. 11 − 13 This is particularly important for warm dense matter (WDM), 14 − 16 which is a state of matter generated for example by laser heating or shock compression at facilities such as the European X-ray Free-Electron Laser (XFEL) 17 and Linac coherent light source (LCLS) at SLAC 18 and naturally occurs in astrophysical objects like the interior of giant planets. 18 , 19 Important technological applications of WDM include the discovery of novel materials under extreme conditions 20 − 22 and hot-electron chemistry.…”

“… 11 − 13 This is particularly important for warm dense matter (WDM), 14 − 16 which is a state of matter generated for example by laser heating or shock compression at facilities such as the European X-ray Free-Electron Laser (XFEL) 17 and Linac coherent light source (LCLS) at SLAC 18 and naturally occurs in astrophysical objects like the interior of giant planets. 18 , 19 Important technological applications of WDM include the discovery of novel materials under extreme conditions 20 − 22 and hot-electron chemistry. 23 Therefore, a rigorous understanding of hybrid XC functionals within the generalized KS-DFT approach is of immense importance for physics and quantum chemistry under both ambient and extreme conditions.…”

“…Commonly used orbital-dependent XC functionals belong to the class of hybrid functionals that mix exact Hartree–Fock (HF) exchange with the exchange energy obtained from a density functional approximation, e.g., on the level of the local density approximation (LDA) and the generalized density approximation (GGA). , The success of hybrid XC functionals stems from the reduction of the infamous self-interaction (or delocalization) error, which often hinders explicit density XC functionals like LDA and GGA from reaching chemical accuracy . Additionally, hybrid XC functionals enable thermal XC effects , to be treated more accurately than usual ground-state functionals due to the inherent use of thermally smeared occupation numbers. − This is particularly important for warm dense matter (WDM), − which is a state of matter generated for example by laser heating or shock compression at facilities such as the European X-ray Free-Electron Laser (XFEL) and Linac coherent light source (LCLS) at SLAC and naturally occurs in astrophysical objects like the interior of giant planets. , Important technological applications of WDM include the discovery of novel materials under extreme conditions − and hot-electron chemistry . Therefore, a rigorous understanding of hybrid XC functionals within the generalized KS-DFT approach is of immense importance for physics and quantum chemistry under both ambient and extreme conditions.…”