Importance of van der Waals interaction on structural, vibrational, and thermodynamic properties of NaCl. (May 2018)

• Record Type: Journal Article
• Authors: Marcondes, Michel L.; Wentzcovitch, Renata M.; Assali, Lucy V.C.
• Is Part Of: Solid state communications. Volume 273(2018)
• Page Start: 11
• Page End: 16
• Publication Date: 2018-05
• Subjects: A. NaCl -- D. Equation of state -- D. van der Waals -- D. High pressure; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2018.01.008
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: 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 B 1 to B 2 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. Highlights: van der Waals interaction is key to improving the description of bonds in NaCl. LDA and GGA functionals augmented by dispersive vdW interaction result in a remarkable improvement in the NaCl properties. Anharmonic effects are quite sensitive to the choice of exchange-correlation functional.