A high P-T single-crystal X-ray diffraction study of thermoelasticity of MgSiO 3 orthoenstatite

摘要: P-V-T data of MgSiO3 orthoenstatite have been measured by single-crystal X-ray diffraction at simultaneous high pressures (in excess 4.5 GPa) and temperatures (up to 1000 K). The new the orthoenstatite, together with previous compression thermal expansion data, are described a modified Birch-Murnaghan equation state for diverse temperatures. fitted thermoelastic parameters are: ∂α/∂P values a=2.86(29)×10-5 K-1 b=0.72(16)×10-8 K-2; isothermal bulk modulus K T o =102.8(2) GPa; pressure derivative K′=∂K/∂P=10.2(1.2); temperature K=∂K/∂T=-0.037(5) GPa/K. derived Gruneisen parameter is γ th=1.05 ambient conditions; Anderson-Gruneisen δ =11.6, ∂α/∂P=-3.5×10-6K-1 GPa-1. From state, expansions two constant 1.5 GPa 4.0 calculated. resulting dependence Δα/ΔP=-3.2(1)× 10-6 significantly large K′, K, indicate that compression/expansion very sensitive changes temperature.