Ultrafast transformation of graphite to diamond: an ab initio study of graphite under shock compression.
We report herein ab initio molecular dynamics simulations of graphite under shock compression in conjunction with the multiscale shock technique. Our simulations reveal that a novel short-lived layered diamond intermediate is formed within a few hundred of femtoseconds upon shock loading at a shock velocity of 12 kms (longitudinal stress>130 GPa), followed by formation of cubic diamond. The layered diamond state differs from the experimentally observed hexagonal diamond intermediate found at lower pressures and previous hydrostatic calculations in that a rapid buckling of the graphitic planes produces a mixture of hexagonal and cubic diamond (layered diamond). Direct calculation of the x-ray absorption spectra in our simulations reveals that the electronic structure of the final state closely resembles that of compressed cubic diamond.
Chemical and Materials Science Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA. chris.mundy@pnl.gov
Christopher J
CJ
Mundy
Alessandro
A
Curioni
Nir
N
Goldman
I-F
IF
Will Kuo
Evan J
EJ
Reed
Laurence E
LE
Fried
Marcella
M
Ianuzzi
D000465:Algorithms; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D018130:Diamond / Q000737:chemistry*; D004583:Electrons; D004735:Energy Transfer; D006108:Graphite / Q000737:chemistry*; D008968:Molecular Conformation; D053838:Scattering, Small Angle; D013052:Spectrometry, X-Ray Emission / Q000379:methods; D013997:Time Factors
D018130:Diamond; D006108:Graphite