81 research outputs found
Observation and analysis of Fano-like lineshapes in the Raman spectra of molecules adsorbed at metal interfaces
Surface enhanced Raman spectra from molecules (bipyridyl ethylene) adsorbed
on gold dumbells are observed to become increasingly asymmetric (Fano-like) at
higher incident light intensity. The electronic temperature (inferred from the
anti-Stokes (AS) electronic Raman signal increases at the same time while no
vibrational AS scattering is seen. These observations are analyzed by assuming
that the molecule-metal coupling contains an intensity dependent contribution
(resulting from light-induced charge transfer transitions as well as
renormalization of the molecule metal tunneling barrier). We find that
interference between vibrational and electronic inelastic scattering routes is
possible in the presence of strong enough electron-vibrational coupling and can
in principle lead to the observed Fano-like feature in the Raman scattering
profile. However the best fit to the observed results, including the dependence
on incident light intensity and the associated thermal response is obtained
from a model that disregards this coupling and accounts for the structure of
the continuous electronic component of the Raman scattering signal. The
temperatures inferred from the Raman signal are argued to be only of
qualitative value.Comment: 20 pages, 12 figure
Iliotibial band release as an adjunct to the surgical management of patellar stress fracture in the athlete: a case report and review of the literature
Stress fracture of the patella is rare. In this report, a case of patellar stress fracture occurring in an amateur athlete is presented, and an operative adjunct to the surgical management of this condition is proposed
Electronic Structure and Bonding of Icosahedral Core-Shell Gold-Silver Nanoalloy Clusters Au_(144-x)Ag_x(SR)_60
Atomically precise thiolate-stabilized gold nanoclusters are currently of
interest for many cross-disciplinary applications in chemistry, physics and
molecular biology. Very recently, synthesis and electronic properties of
"nanoalloy" clusters Au_(144-x)Ag_x(SR)_60 were reported. Here, density
functional theory is used for electronic structure and bonding in
Au_(144-x)Ag_x(SR)_60 based on a structural model of the icosahedral
Au_144(SR)_60 that features a 114-atom metal core with 60 symmetry-equivalent
surface sites, and a protecting layer of 30 RSAuSR units. In the optimal
configuration the 60 surface sites of the core are occupied by silver in
Au_84Ag_60(SR)_60. Silver enhances the electron shell structure around the
Fermi level in the metal core, which predicts a structured absorption spectrum
around the onset (about 0.8 eV) of electronic metal-to-metal transitions. The
calculations also imply element-dependent absorption edges for Au(5d)
\rightarrow Au(6sp) and Ag(4d) \rightarrow Ag(5sp) interband transitions in the
"plasmonic" region, with their relative intensities controlled by the Ag/Au
mixing ratio.Comment: 4 figure
Integrating dispersal proxies in ecological and environmental research in the freshwater realm
Directed Cultural Probes: Detecting Barriers in the Usage of Public Transportation
Part 2: Long and Short PapersInternational audienceIn this paper we describe the application of a variation of cultural probing for identifying barriers in the use of public transportation for target groups with visual, cognitive or language-related handicaps. To be able to better focus on the targeted aspect - the barriers - we applied modifications to the traditional cultural probing approach: Users were encouraged to generate data related to the targeted aspect. We found that this approach can produce focused results that can be analysed fast and can help to overcome obstacles related to limitations in verbal skills or expressiveness of the user
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