TY - JOUR
T1 - High-pressure equation of State of 1,3,5-triamino-2,4,6-trinitrobenzene
T2 - Insights into the monoclinic phase transition, hydrogen bonding, and anharmonicity
AU - Steele, Brad A.
AU - Stavrou, Elissaios
AU - Prakapenka, Vitali B.
AU - Kroonblawd, Matthew P.
AU - Kuo, Feng I.W.
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/12/17
Y1 - 2020/12/17
N2 - The high-pressure equation of state (EOS) of energetic materials (EMs) is important for continuum and mesoscale models of detonation performance and initiation safety. Obtaining a high-fidelity EOS of the insensitive EM 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) has proven to be difficult because of challenges in experimental characterization at high pressures (HPs). In this work, powder X-ray diffraction patterns were fitted using the recently discovered monoclinic I2/a phase above 4 GPa, which shows that TATB is less compressible than when indexed with the triclinic P1 phase. First-principles calculations were performed with Perdew−Burke−Ernzerhof (PBE) and PBE0 functionals including thermal effects using the P1 phase. PBE0 improves the description of hydrogen bonding and thus predicts accurate planar a and b lattice parameters under ambient conditions. However, discrepancies in the predicted lattice parameters above 4−10 GPa compared with experimental measurements indexed with P1 are further evidence of a structural modification at high pressure. Layer sliding defects are formed during molecular dynamics simulations, which induces an anharmonic effect on the thermal expansion of the c lattice parameter. In short, the results provide several insights into determining high-fidelity EOS parameters for TATB and other molecular crystals.
AB - The high-pressure equation of state (EOS) of energetic materials (EMs) is important for continuum and mesoscale models of detonation performance and initiation safety. Obtaining a high-fidelity EOS of the insensitive EM 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) has proven to be difficult because of challenges in experimental characterization at high pressures (HPs). In this work, powder X-ray diffraction patterns were fitted using the recently discovered monoclinic I2/a phase above 4 GPa, which shows that TATB is less compressible than when indexed with the triclinic P1 phase. First-principles calculations were performed with Perdew−Burke−Ernzerhof (PBE) and PBE0 functionals including thermal effects using the P1 phase. PBE0 improves the description of hydrogen bonding and thus predicts accurate planar a and b lattice parameters under ambient conditions. However, discrepancies in the predicted lattice parameters above 4−10 GPa compared with experimental measurements indexed with P1 are further evidence of a structural modification at high pressure. Layer sliding defects are formed during molecular dynamics simulations, which induces an anharmonic effect on the thermal expansion of the c lattice parameter. In short, the results provide several insights into determining high-fidelity EOS parameters for TATB and other molecular crystals.
UR - http://www.scopus.com/inward/record.url?scp=85097752435&partnerID=8YFLogxK
U2 - 10.1021/acs.jpca.0c09463
DO - 10.1021/acs.jpca.0c09463
M3 - 文章
C2 - 33267581
AN - SCOPUS:85097752435
SN - 1089-5639
VL - 124
SP - 10580
EP - 10591
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 50
ER -