Strong polarization-induced reduction of addition energies in single-molecule nanojunctions

We address polarization-induced renormalization of molecular levels in solid-state based single-molecule transistors and focus on an organic conjugate molecule where a surprisingly large reduction of the addition energy has been observed. We have developed a scheme that combines a self-consistent solution of a quantum chemical calculation with a realistic description of the screening environment. Our results indeed show a large reduction, and we explain this to be a consequence of both (a) a reduction of the electrostatic molecular charging energy and (b) polarization induced level shifts of the HOMO and LUMO levels. Finally, we calculate the charge stability diagram and explain at a qualitative level general features observed experimentally.Comment: 9 pages, 5 figure

Dynamic image potential at an Al(111) surface

We evaluate the electronic self-energy Sigma(E) at an Al(111) surface using the GW space-time method. This self-energy automatically includes the image potential V-im not present in any local-density approximation for exchange and correlation. We solve the energy-dependent quasiparticle equations and calculate the effective local potential experienced by electrons in the near-surface region. The relative contribution of exchange proves to be very different for states above the Fermi level. The image-plane position for interacting electrons is closer to the surface than for the purely electrostatic effects felt by test charges, and, like its classical counterpart, is drawn inwards by the effects of atomic structure

Stripes, Vibrations and Superconductivity

We propose a model of a spatially modulated collective charge state of superconducting cuprates. The regions of higher carrier density (stripes) are described in terms of Luttinger liquids and the regions of lower density as a two-dimensional interacting bosonic gas of d_{x^2-y^2} hole pairs. The interactions among the elementary excitations are repulsive and the transition to the superconducting state is driven by decay processes. Vibrations of the CCS and the lattice, although not participating directly in the binding mechanism, are fundamental for superconductivity. The superfluid density and the lattice have a strong tendency to modulation implying a still unobserved dimerized stripe phase in cuprates. The phase diagram of the model has a crossover from 1D to 2D behavior and a pseudogap region where the amplitude of the order parameters are finite but phase coherence is not established. We discuss the nature of the spin fluctuations and the unusual isotope effect within the model.Comment: 51 pages, 20 figures. Post-March Meeting version: New references are added, some of the typos are corrected, and a few new discussions are include

Careers of highly educated self-initiated expatriates : observations from studies among Finnish business professionals

This chapter reviews existing literature about the careers of self-initiated expatriates and analyzes the different studies carried out among university level educated Finnish business professionals. A series of studies carried out among members of the Finnish Association of Business School Graduates during the last 15 years was cross-analyzed. The studies are based on three surveys and further interviews among their expatriate members (1999, 2004 and a follow-up study in 2012) also involving SIEs. Therefore, this chapter provide an overview of what we know about the careers of Finnish SIEs and show evidence of (1) their career motives, (2) the role of family considerations in the career decision making of SIEs, (3) the development of career capital and social capital during SIE-experiences, and also (4) longer-term career impacts of SIE-experiences. Based on the literature review and analysis of above mentioned studies we highlight the gaps in in the knowledge about SIEs and suggest areas where further research is needed.fi=vertaisarvioitu|en=peerReviewed

Modeling of synthesis and flow properties of propylene-diene copolymers

Copolymerization with nonconjugated dienes offers an attractive route for introducing long-chain branching in polypropylene. From a simplified set of rate equations for such copolymerization with a metallocene catalyst, we derive the probabilities of branch formation at different stages of the reaction in a semibatch reactor. Using these probabilities, we generate an ensemble of molecules via a Monte Carlo sampling. The knowledge of the branching topology and segment lengths allows us to compute the flow properties of the resins from computational rheology. We compare our model predictions with existing experimental data, namely the molar mass distribution and small amplitude oscillatory shear response, for a set of resins with varying diene content. The rheology data suggest that the entanglement time Ï.,e depends sensitively and in a well-defined fashion on the diene content

Reverse flow in academic mobility from core to periphery:Motivations of international faculty working in Kazakhstan

Through expanding flows of labor and knowledge on a global scale, academics are increasingly mobile as higher education institutions compete for talent that transcends borders. However, talent often flows from the periphery to the core as scholars seek out employment in recognized institutions of higher learning in developed economies. This study examines faculty mobility in a reverse direction: from the core to Kazakhstan, the largest country in Central Asia. What factors persuade faculty members to relocate to Kazakhstan for full-time employment? What types of individuals pursue this relocation? Through interviews with international faculty members based in Kazakhstan, the study identifies push factors that trigger departure from one’s previous country of residence: job market, unsatisfactory work conditions, age, and marital status. Alternatively, Kazakhstan attracts scholars via pull factors that include salary, sense of adventure, and the opportunity to build new institutions and programs as well as conduct research. Unlike previous studies that highlight boundaryless mobility and individual agency, this study reveals constraints that mediate international faculty mobility. Furthermore, salary plays a limited role as a pull factor particularly among early career academics who are seeking research opportunities and meaningful contributions in building new academic programs and institutions