vdW-DF Study of energetic, structural, and vibrational properties of small water clusters and ice Ih

TL;DR

This study uses the van der Waals density functional (vdW-DF) to accurately analyze the energetic, structural, and vibrational properties of small water clusters and ice Ih, showing improvements over standard functionals and aligning well with experiments.

Contribution

The paper demonstrates that vdW-DF provides a systematic and consistent improvement in modeling water systems compared to traditional density functional approximations.

Findings

vdW-DF results agree well with experiments and quantum chemistry

vdW-DF outperforms standard exchange-correlation functionals

Provides insights into failures of standard functionals in water modeling

Abstract

We present results for a density functional theory study of small water clusters and hexagonal ice Ih, using the van der Waals density functional (vdW-DF). In particular, we examine energetic, structural, and vibrational properties of these systems. Our results exhibit excellent agreement with both experiment and quantum-chemistry calculations and show a systematic and consistent improvement over standard exchange-correlation functionals---making vdW-DF a promising candidate for resolving longstanding difficulties with density functional theory in describing water. In addition, by comparing our vdW-DF results with quantum-chemistry calculations and other standard exchange-correlation functionals, we shed light on the question of why standard functionals often fail to describe these systems accurately.