1206.0775 (Kyuho Lee et al.)

Benchmarking van der Waals Density Functionals with Experimental Data:
Potential Energy Curves for H2 Molecules on Cu(111), (100), and (110)
Surfaces    [PDF]

Kyuho Lee, Kristian Berland, Mina Yoon, Stig Andersson, Elsebeth Schroder, Per Hyldgaard, Bengt I. Lundqvist

Detailed physisorption data from experiment for the H_2 molecule on low-index Cu surfaces challenge theory. Recently, density-functional theory (DFT) has been developed to account for nonlocal correlation effects, including van der Waals (dispersion) forces. We show that the functional vdW-DF2 gives a potential-energy curve, potential-well energy levels, and difference in lateral corrugation promisingly close to the results obtained by resonant elastic backscattering-diffraction experiments. The backscattering barrier is found selective for choice of exchange-functional approximation. Further, the DFT-D3 and TS-vdW corrections to traditional DFT formulations are also benchmarked, and deviations are analyzed.

View original: http://arxiv.org/abs/1206.0775