Electronic structure and dimerization of a single monatomic gold wire

The electronic structure of a single monatomic gold wire is presented for the first time. It has been obtained with state-of-the-art ab-initio full-potential density-functional (DFT) LMTO (linearized muffin-tin orbital) calculations taking into account relativistic effects. For stretched structures in the experimentally accessible range the conduction band is exactly half-filled, whereas the band structures are more complex for the optimized structure. By studying the total energy as a function of unit-cell length and of a possible bond-length alternation we find that the system can lower its total energy by letting the bond lengths alternate leading to a structure containing separated dimers with bond lengths of about 2.5 \AA, largely independent of the stretching. However, first for fairly large unit cells (above roughly 7 \AA), is the total-energy gain upon this dimerization comparable with the energy costs upon stretching. We propose that this together with band-structure effects is the reason for the larger interatomic distances observed in recent experiments. We find also that although spin-orbit couplings lead to significant effects on the band structure, the overall conclusions are not altered, and that finite Au_2, Au_4, and Au_6 chains possess electronic properties very similar to those of the infinite chain.Comment: (14 pages, 5 figures; Elsevier Preprint style elsart.sty

Political Islam and Europe - Views from the Arab Mediterranean states and Turkey. CEPS Working Document, No. 264, 10 April 2007

The social, political and economic power of moderate Middle East and North African Islamist movements has been growing for a generation or so. The question of how to deal with Islamists who reject violence, embrace democracy and outperform their competitors at the polls has therefore become a central concern not only of incumbent Middle East elites, but also of interested foreign actors such as the EU and US. Robert Springborg sees the need for the EU to clarify its policies towards the MENA region and Muslim democrats within it. The present lack of EU policies on engaging with moderate Islamists leads them to be at best curious about the EU and at worse to be suspicious of it. Engagement might itself help to contribute to policy formation in this important area, and serve as a vehicle to disseminate information about relevant EU policies

Non-universality of commonly used correlation-energy density functionals

The correlation energies of the helium isoelectronic sequence and of Hooke's atom isoelectronic sequence have been evaluated using an assortment of local, gradient and meta-gradient density functionals. The results are compared with the exact correlation energies, showing that while several of the more recent density functionals reproduce the exact correlation energies of the helium isoelectronic sequence rather closely, none is satisfactory for Hooke's atom isoelectronic sequence. It is argued that the uniformly acceptable results for the helium sequence can be explained through simple scaling arguments that do not hold for Hooke's atom sequence, so that the latter system provides a more sensitive testing ground for approximate density functionals. This state of affairs calls for further effort towards formulating correlation-energy density functionals that would be truly universal at least for spherically-symmetric two-fermion systems.Comment: To appear in J. Chem. Phy

Structural and electronic properties of Si/Ge nanoparticles

Results of a theoretical study of the electronic properties of (Si)Ge and (Ge)Si core/shell nanoparticles, homogeneous SiGe clusters, and Ge$|$Si clusters with an interphase separating the Si and Ge atoms are presented. In general, (Si)Ge particles are more stable than (Ge)Si ones, and SiGe systems are more stable than Ge$|$Si ones. It is found that the frontier orbitals, that dictate the optical properties, are localized to the surface, meaning that saturating dangling bonds on the surface with ligands may influence the optical properties significantly. In the central parts we identify a weak tendency for the Si atoms to accept electrons, whereas Ge atoms donate electrons.Comment: To appear in Phys. Rev.

Arts-based methods for facilitating meta-level learning in management education: Making and expressing refined perceptual distinctions

Arts-based methods are increasingly used to facilitate meta-level learning in management education. Such increased use suggests that these methods are relevant and offer a unique contribution meeting a need in today’s management education. Yet, the literature is not clear on what this unique contribution may be even though it abounds with suggestions of varying quality. To explore this matter, I conduct a systematic literature review focused on arts-based methods, management education, and meta-level learning. I find that the unique contribution of arts-based methods is to foreground the process of making and expressing more refined perceptual distinctions, not to get accurate data, but as integral to our thinking/learning. This finding is important, because it imply that certain (commonly applied) ways of using arts-based methods may limit their potential. Finally, I suggest that future research regarding arts-based methods should focus on exploring the impact the process of learning to make and express more refined perceptual distinctions may have on managerial practice to further understand the relevance of these methods to managers

Thomas Hobbes and the Political Economy of Peace

Thomas Hobbes’s theory of war is currently being re-examined as part of a re-examination of realism in international relations theory which claims to be Hobbes-based. I am not alone in maintaining that Hobbes was first and foremost a peace theorist, rejecting the usual grounds for war, pretexts based on just war, infringements on property or trade, and thus trespass. But those who examine the three-fold causes of war that Hobbes gives, as “competition”, “diffidence”, and “glory”, have generally not noticed the relation between Hobbes’s theory of war and empire. While Hobbes makes remarkably few references to the colonial ventures of Great Britain, for reasons that we will consider, his theory of empire, like his theory of war, is based on classical notions of internal balance and the homeostasis of the body politic along Aristotelian lines. His treatment of the polity as a natural body is consistent with his materialist ontology and he treats war and empire in terms of both “intestine diseases” and pathologies that afflict the body politic from without. The upshot is a theory remarkably backward-looking in terms of its emphasis on the health of the body politic and the politics of balance, which forbid “vain-glorious wars” and demand that overly-powerful subjects, towns of “immoderate greatness” and grandiose enlargements of dominion be excised, like Aristotle’s “big foot” whose disproportion spoils the proportion of the body as a whole

Volume 2: Development Models in Muslim Contexts : Chinese, \u27Islamic\u27 and Neo-liberal Alternatives

Recent discussions of the \u27Chinese economic development model\u27, the emergence of an alternative \u27Muslim model\u27 over the past quarter century and the faltering globalisation of the \u27Washington Consensus\u27 all point to the need to investigate more systematically the nature of these models and their competitive attractions. This is especially the case in the Muslim world which both spans different economic and geographic categories and is itself the progenitor of a development model. The \u27Chinese model\u27 has attracted the greatest attention in step with that country\u27s phenomenal growth and therefore provides the primary focus for this book. This volume examines the characteristics of this model and its reception in two major regions of the world - Africa and Latin America. It also investigates the current competition over development models across Muslim contexts. The question of which model or models, if any, will guide development in Muslim majority countries is vital not only for them, but for the world as a whole. This is the first political economy study to address this vital question as well as the closely related issue of the centrality of governance to development.https://ecommons.aku.edu/uk_ismc_series_emc/1003/thumbnail.jp