3,610 research outputs found
An Analysis of Mature Consumers\u27 Reactions to Unsatisfactory Complaint Handling by Service Provider
In this nationwide survey, consumers over the age of 65 reported their reactions to a recalled unsatisfactory complaint experience that involved a service rendered. The study focused on the possible link between attributions of complainants for failure to obtain desired outcomes and subsequent behaviors. Inferences about causes and some demographic characteristics were found useful for explaining variation in anger reactions, negative word-of-mouth communications, repurchase behaviors, and estimations of the likelihood of future complaint actions among sampled seniors. Implications of results in terms of effective complaint handling by service organizations are discussed
Magnetic exchange interaction between rare-earth and Mn ions in multiferroic hexagonal manganites
We report a study of magnetic dynamics in multiferroic hexagonal manganite
HoMnO3 by far-infrared spectroscopy. Low-temperature magnetic excitation
spectrum of HoMnO3 consists of magnetic-dipole transitions of Ho ions within
the crystal-field split J=8 manifold and of the triangular antiferromagnetic
resonance of Mn ions. We determine the effective spin Hamiltonian for the Ho
ion ground state. The magnetic-field splitting of the Mn antiferromagnetic
resonance allows us to measure the magnetic exchange coupling between the
rare-earth and Mn ions.Comment: accepted for publication in Physical Review Letter
Highly efficient double ionization of mixed alkali dimers by intermolecular Coulombic decay
As opposed to purely molecular systems where electron dynamics proceed only
through intramolecular processes, weakly bound complexes such as He droplets
offer an environment where local excitations can interact with neighbouring
embedded molecules leading to new intermolecular relaxation mechanisms. Here,
we report on a new decay mechanism leading to the double ionization of alkali
dimers attached to He droplets by intermolecular energy transfer. From the
electron spectra, the process is similar to the well-known shake-off mechanism
observed in double Auger decay and single-photon double ionization, however, in
this case, the process is dominant, occurring with efficiencies equal to, or
greater than, single ionization by energy transfer. Although an alkali dimer
attached to a He droplet is a model case, the decay mechanism is relevant for
any system where the excitation energy of one constituent exceeds the double
ionization potential of another neighbouring molecule. The process is, in
particular, relevant for biological systems, where radicals and slow electrons
are known to cause radiation damageComment: accepted as Nature Physic
Experimental observations of topologically guided water waves within non-hexagonal structures
We investigate symmetry-protected topological water waves within a strategically engineered square lattice system. Thus far, symmetry-protected topological modes in hexagonal systems have primarily been studied in electromagnetism and acoustics, i.e. dispersionless media. Herein, we show experimentally how crucial geometrical properties of square structures allow for topological transport that is ordinarily forbidden within conventional hexagonal structures. We perform numerical simulations that take into account the inherent dispersion within water waves and devise a topological insulator that supports symmetry-protected transport along the domain walls. Our measurements, viewed with a high-speed camera under stroboscopic illumination, unambiguously demonstrate the valley-locked transport of water waves within a non-hexagonal structure. Due to the tunability of the energy's directionality by geometry, our results could be used for developing highly-efficient energy harvesters, filters and beam-splitters within dispersive media
Ion-lithium collision dynamics studied with an in-ring MOTReMi
We present a novel experimental tool allowing for kinematically complete
studies of break-up processes of laser-cooled atoms. This apparatus, the
'MOTReMi', is a combination of a magneto-optical trap (MOT) and a Reaction
Microscope (ReMi). Operated in an ion-storage ring, the new setup enables to
study the dynamics in swift ion-atom collisions on an unprecedented level of
precision and detail. In first experiments on collisions with 1.5 MeV/amu
O-Li the pure ionization of the valence electron as well as
ionization-excitation of the lithium target has been investigated
Collective Autoionization in Multiply-Excited Systems: A novel ionization process observed in Helium Nanodroplets
Free electron lasers (FELs) offer the unprecedented capability to study
reaction dynamics and image the structure of complex systems. When multiple
photons are absorbed in complex systems, a plasma-like state is formed where
many atoms are ionized on a femtosecond timescale. If multiphoton absorption is
resonantly-enhanced, the system becomes electronically-excited prior to plasma
formation, with subsequent decay paths which have been scarcely investigated to
date. Here, we show using helium nanodroplets as an example that these systems
can decay by a new type of process, named collective autoionization. In
addition, we show that this process is surprisingly efficient, leading to ion
abundances much greater than that of direct single-photon ionization. This
novel collective ionization process is expected to be important in many other
complex systems, e.g. macromolecules and nanoparticles, exposed to high
intensity radiation fields
Inelastic scattering of photoelectrons from He nanodroplets
We present a detailed study of inelastic energy-loss collisions of
photoelectrons emitted from He nanodroplets by tunable extreme ultraviolet
(XUV) radiation. Using coincidence imaging detection of electrons and ions, we
probe the lowest He droplet excited states up to the electron impact ionization
threshold. We find significant signal contributions from photoelectrons emitted
from free He atoms accompanying the He nanodroplet beam. Furthermore, signal
contributions from photoionization and electron impact excitation/ionization
occurring in pairs of nearest-neighbor atoms in the He droplets are detected.
This work highlights the importance of inelastic electron scattering in the
interaction of nanoparticles with XUV radiation
Real-time dynamics of the formation of hydrated electrons upon irradiation of water clusters with extreme ultraviolet light
Free electrons in a polar liquid can form a bound state via interaction with the molecular environment. This so-called hydrated electron state in water is of fundamental importance e.g.~in cellular biology or radiation chemistry. Hydrated electrons are highly reactive radicals that can either directly interact with DNA or enzymes, or form highly excited hydrogen (Hâ) after being captured by protons. Here, we investigate the formation of the hydrated electron in real-time employing XUV femtosecond pulses from a free electron laser, in this way observing the initial steps of the hydration process. Using time-resolved photoelectron spectroscopy we find formation timescales in the low picosecond range and resolve the prominent dynamics of forming excited hydrogen states
Two-Stage Rotational Disordering of a Molecular Crystal Surface: C60
We propose a two-stage mechanism for the rotational surface disordering phase
transition of a molecular crystal, as realized in C fullerite. Our
study, based on Monte Carlo simulations, uncovers the existence of a new
intermediate regime, between a low temperature ordered state,
and a high temperature disordered phase. In the intermediate
regime there is partial disorder, strongest for a subset of particularly
frustrated surface molecules. These concepts and calculations provide a
coherent understanding of experimental observations, with possible extension to
other molecular crystal surfaces.Comment: 4 pages, 2 figure
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