Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session L18: Electronic Structure Methods
11:15 AM–2:15 PM,
Wednesday, March 7, 2018
LACC Room: 306B
Sponsoring Units: DCOMP DMP
Chair: Efthimios Kaxiras, Harvard Univ
Abstract: L18.00006 : Importance of van der Waals interaction on structural, vibrational, and thermodynamics properties of NaCl*
12:15 PM–12:27 PM
(University of Sao Paulo)
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. Our results reveal i) 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 ii) great sensitivity of anharmonic effects on the choice of XC functional.
*MLM and LVCA thank support by the CNPq. MLM also thanks support by CAPES - grant BEX 14456/13-3. RMW and MLM were supported by NSF grants 1161023 and 1348066.
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