The first principles methods, density-functional theory and quantum Monte Carlo, have been used to examine the balance between van der Waals (vdW) forces and hydrogen bonding in ambient and high-pressure phases of ice. At higher pressure, the contribution to the lattice energy from vdW increases and that from hydrogen bonding decreases, leading vdW to have a substantial effect on the transition pressures between the crystalline ice phases. An important consequence, likely to be of relevance to molecular crystals in general, is that transition pressures obtained from density-functional theory exchange-correlation functionals which neglect vdW forces are greatly overestimated.
Hydrogen Bonds and van der Waals Forces in Ice at Ambient and High Pressures / Santra, B; Klimes, J; Alfe, D; Tkatchenko, A; Slater, B; Michaelides, A; Car, R; Scheffler, M. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 107:18(2011). [10.1103/PhysRevLett.107.185701]
Hydrogen Bonds and van der Waals Forces in Ice at Ambient and High Pressures
Alfe D;
2011
Abstract
The first principles methods, density-functional theory and quantum Monte Carlo, have been used to examine the balance between van der Waals (vdW) forces and hydrogen bonding in ambient and high-pressure phases of ice. At higher pressure, the contribution to the lattice energy from vdW increases and that from hydrogen bonding decreases, leading vdW to have a substantial effect on the transition pressures between the crystalline ice phases. An important consequence, likely to be of relevance to molecular crystals in general, is that transition pressures obtained from density-functional theory exchange-correlation functionals which neglect vdW forces are greatly overestimated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.