naa a22 4500 510772625 CHVBK 20180411083219.0 cr unu---uuuuu 180411e20131101xx s 000 0 eng 10.1007/s11837-013-0735-8 doi (NATIONALLICENCE)springer-10.1007/s11837-013-0735-8 Oxygen Atom Adsorption on and Diffusion into Nb(110) and Nb(100) from First Principles [Elektronische Daten] [De Tafen, Michael Gao] To understand the dynamics of oxidation of Nb, we examine the adsorption, absorption, and diffusion of an oxygen atom on, in, and into Nb(110) and Nb(100) surfaces, respectively, using density functional theory. Our calculations predict that the oxygen atom adsorbs on the threefold site on Nb(110) and the fourfold hollow site on Nb(100), and the adsorption energy is −5.08eV and −5.18eV, respectively. We find the long and short bridge sites to be transition states for O diffusion on Nb(110), while the on-top site is a rank-2 saddle point. In the subsurface region, the oxygen atom prefers the octahedral site, as in bulk niobium. Our results show also that the O atom is more stable on Nb(110) subsurface than on Nb(100) subsurface. The diffusion of oxygen atoms into niobium surfaces passes through transition states where the oxygen atom is coordinated to four niobium atoms. The diffusion barriers of the oxygen atom into Nb(110) and Nb(100) are 1.81eV and 2.05eV, respectively. An analysis of the electronic density of states reveals the emergence of well-localized electronic states below the lowest states of clean Nb surfaces due to d-p orbital hybridization. TMS (outside the USA), 2013 Tafen De National Energy Technology Laboratory, 1450 Queen Ave. SW, 97321, Albany, OR, USA aut Gao Michael National Energy Technology Laboratory, 1450 Queen Ave. SW, 97321, Albany, OR, USA aut JOM Springer US; http://www.springer-ny.com 65/11(2013-11-01), 1473-1481 1047-4838 65:11<1473 2013 65 11837 https://doi.org/10.1007/s11837-013-0735-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11837-013-0735-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Tafen De National Energy Technology Laboratory, 1450 Queen Ave. SW, 97321, Albany, OR, USA aut NATIONALLICENCE 700 1- Gao Michael National Energy Technology Laboratory, 1450 Queen Ave. SW, 97321, Albany, OR, USA aut NATIONALLICENCE 773 0- JOM Springer US; http://www.springer-ny.com 65/11(2013-11-01), 1473-1481 1047-4838 65:11<1473 2013 65 11837 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer