TY - JOUR
T1 - Importance of van der Waals interaction on structural, vibrational, and thermodynamic properties of NaCl
AU - Marcondes, Michel L.
AU - Wentzcovitch, Renata M.
AU - Assali, Lucy V.C.
PY - 2018/5
Y1 - 2018/5
N2 - Thermal equations of state (EOS) are essential in several scientific domains. However, experimental determination of EOS parameters may be limited at extreme conditions, therefore, ab initio calculations have become an important method to obtain them. Density functional theory (DFT) and its extensions with various degrees of approximations for the exchange and correlation (XC) energy is the method of choice, but large errors in the EOS parameters are still common. The alkali halides have been problematic from the onset of this field and the quest for appropriate DFT functionals for such ionic and relatively weakly bonded systems has remained an active topic of research. Here we use DFT + van der Waals functionals to calculate vibrational properties, thermal EOS, thermodynamic properties, and the B1 to B2 phase boundary of NaCl with high precision. Our results reveal a remarkable improvement over the performance of standard local density approximation and generalized gradient approximation functionals for all these properties and phase transition boundary, as well as great sensitivity of anharmonic effects on the choice of XC functional.
AB - Thermal equations of state (EOS) are essential in several scientific domains. However, experimental determination of EOS parameters may be limited at extreme conditions, therefore, ab initio calculations have become an important method to obtain them. Density functional theory (DFT) and its extensions with various degrees of approximations for the exchange and correlation (XC) energy is the method of choice, but large errors in the EOS parameters are still common. The alkali halides have been problematic from the onset of this field and the quest for appropriate DFT functionals for such ionic and relatively weakly bonded systems has remained an active topic of research. Here we use DFT + van der Waals functionals to calculate vibrational properties, thermal EOS, thermodynamic properties, and the B1 to B2 phase boundary of NaCl with high precision. Our results reveal a remarkable improvement over the performance of standard local density approximation and generalized gradient approximation functionals for all these properties and phase transition boundary, as well as great sensitivity of anharmonic effects on the choice of XC functional.
KW - A. NaCl
KW - D. Equation of state
KW - D. High pressure
KW - D. van der Waals
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U2 - 10.1016/j.ssc.2018.01.008
DO - 10.1016/j.ssc.2018.01.008
M3 - Article
AN - SCOPUS:85042217120
SN - 0038-1098
VL - 273
SP - 11
EP - 16
JO - Solid State Communications
JF - Solid State Communications
ER -