ﻻ يوجد ملخص باللغة العربية
A wetting transition occurs when the contact angle of a liquid drop on a surface changes from a nonzero value to zero. Such a transition has never been observed for water on any solid surface. This paper discusses the value of the temperature T_w at which the transition should occur for water on graphite. A simple model, previously used for nonpolar fluids, predicts the value of $T_w$ as a function of the well-depth D of the adsorption potential. While $D$ is not well known for the case of water/graphite, the model implies that T_w is likely to fall in the range 350 to 500 K. Experimental search for this transition is warranted. Water wetting transition temperatures on other surfaces are also discussed.
The relation between the contact angle of a liquid drop and the morphological parameters of self-affine solid surfaces have been investigated. We show experimentally that the wetting property of a solid surface crucially depends on the surface morpho
We present a combined experimental and theoretical study of the self-diffusion of ammonia on exfoliated graphite. Using neutron time-of-flight spectroscopy we are able to resolve the ultrafast diffusion process of adsorbed ammonia, NH$_3$, on graphit
Density functional theory (DFT) is widely used in surface science, but gives poor accuracy for oxide surface processes, while high-level quantum chemistry methods are hard to apply without losing basis-set quality. We argue that quantum Monte Carlo t
We present a x-ray dichroism study of graphite surfaces that addresses the origin and magnitude of ferromagnetism in metal-free carbon. We find that, in addition to carbon $pi$ states, also hydrogen-mediated electronic states exhibit a net spin polar
We calculate the electronic structure and magnetic properties of hydrogenated graphite surfaces using van der Waals density functional theory (DFT) and model Hamiltonians. We find, as previously reported, that the interaction between hydrogen atoms o