Volume 117, Issue 18, 08 November 2002
Index of content:
117(2002); http://dx.doi.org/10.1063/1.1519252View Description Hide Description
The metabolism of hydrogen constitutes a central process in the global biological energy cycle. Among all the enzymes that can mediate this process, Fe-only hydrogenases are unique in their particular high reactivity. Recently, some important progresses have been achieved. Following our previous paper [Z.-P. Liu and P. Hu, J. Am. Chem. Soc. 124, 5175 (2002)] that characterizes the individual redox state of the active site of Fe-only hydrogenase, in this work we have determined the feasible reaction pathways and energetics for the metabolism on the active site of Fe-only hydrogenases, using density functional theory. We show that metabolism possesses very low reaction barriers and a proximal base from a nearby protein plays an important role in metabolism.
117(2002); http://dx.doi.org/10.1063/1.1518998View Description Hide Description
Photoelectron (PE) spectra of and were measured at 299 nm (4.154 eV). Photodetachment of these anions accesses the prereactive van der Waals well on the ground statepotential energy surface, as well as the low-lying spin–orbit excited states resulting from the interaction of Cl and with The PE spectra are dominated by two relatively narrow peaks corresponding to transitions to the neutral and complexes. The energetics and widths of these features are interpreted in terms of the properties of the anion and neutral potential energy surfaces.
Dissociative adsorption of NO upon Al(111): Orientation dependent charge transfer and chemisorption reaction dynamics117(2002); http://dx.doi.org/10.1063/1.1519107View Description Hide Description
The dissociative and abstractive chemisorptiondynamics of NO on Al(111) were studied. A higher sticking probability for the N end-on of NO onto Al(111) was measured. In contrast, Auger electron experiments reveal stepped surfaces to be oxygen rich at low coverage after exposure to NO. Density functional theory calculations show (i) a few angstroms from the surface, an N end-on first collision geometry results in electronic structures consistent with charge transfer; (ii) there is stabilization on the surface for N end-on or side-on orientations; (iii) dissociation is enhanced by a partial or full flip of the molecule.