Non-molecular Phases of H2O and HF Under Detonation-like Conditions
Conference
·
OSTI ID:898005
Energetic materials are known to produce simple molecular species, such as HF and H{sub 2}O, during detonation. The behavior of such species under conditions of simultaneous high pressure and temperature are unknown. The predicted high pressure superionic phases of water and HF are investigated via ab initio molecular dynamics. We study water at densities of 2.0-3.0 g/cc (34 -115 GPa) along the 2000 K isotherm. We find that extremely rapid (superionic) diffusion of protons occurs in a fluid phase at pressures between 34 and 58 GPa. A transition to a stable body-centered cubic (bcc) O lattice with superionic proton conductivity is observed between 70 and 75 GPa. We find that all molecular species at pressures greater than 75 GPa are too short lived to be classified as bound states. Up to 95 GPa, we find a solid superionic phase characterized by covalent O-H bonding. Above 95 GPa, a transient network phase is found characterized by symmetric O-OH hydrogen bonding with nearly 50% covalent character. Ab initio molecular dynamics H simulations of HF were conducted at densities of 1.8-4.0 g/cc along the 900 K isotherm. According to our simulations, a unique form of (symmetric) hydrogen bonding could play a significant role in superionic conduction. Our work shows that the Chapman-Jouget and Zeldovich-von Neumann Doring (ZND) states of some energetic materials are close to the molecular to non-molecular transition.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 898005
- Report Number(s):
- UCRL-PROC-222768
- Country of Publication:
- United States
- Language:
- English
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