Cooperative Interplay of van der Waals Forces and Quantum Nuclear Effects on Adsorption: H at Graphene and at Coronene

• Published in: ACS nano Vol. 8; no. 10; pp. 9905 - 9913
• Main Authors: Davidson, Erlend R. M, Klimeš, Jiří, Alfè, Dario, Michaelides, Angelos
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 28.10.2014; American Chemical Society (ACS)
• Subjects: ATOMIC AND MOLECULAR PHYSICS; Barriers; Computer simulation; Density functional theory; Graphene; Mathematical models; Molecular dynamics; path integral molecular dynamics; quantum nuclear effects; Surface chemistry; Van der Waals forces; quantum nuclear effects; path integral molecular dynamics; van der Waals forces; density functional theory
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/nn505578x

The energetic barriers that atoms and molecules often experience when binding to surfaces are incredibly important to a myriad of chemical and physical processes. However, these barriers are difficult to describe accurately with current computer simulation approaches. Two prominent contemporary challenges faced by simulation are the role of van der Waals forces and nuclear quantum effects. Here we examine the widely studied model systems of hydrogen on graphene and coronene using a van der Waals inclusive density functional theory approach together with path integral molecular dynamics at 50 K. We find that both van der Waals and quantum nuclear effects work together in a cooperative manner to dramatically reduce the barriers for hydrogen atoms to adsorb. This suggests that the low temperature hydrogenation of graphene is easier than previously thought and in more general terms that the combined roles of van der Waals and quantum tunnelling can lead to qualitative changes in adsorption.