673 research outputs found
MARVEL: measured active rotational-vibrational energy levels
An algorithm is proposed, based principally on an earlier proposition of Flaud and co-workers [Mol. Phys. 32 (1976) 499], that inverts the information contained in uniquely assigned experimental rotational-vibrational transitions in order to obtain measured active rotational-vibrational energy levels (MARVEL). The procedure starts with collecting, critically evaluating, selecting, and compiling all available measured transitions, including assignments and uncertainties, into a single database. Then, spectroscopic networks (SN) are determined which contain all interconnecting rotational-vibrational energy levels supported by the grand database of the selected transitions. Adjustment of the uncertainties of the lines is performed next, with the help of a robust weighting strategy, until a self-consistent set of lines and uncertainties is achieved. Inversion of the transitions through a weighted least-squares-type procedure results in MARVEL energy levels and associated uncertainties. Local sensitivity coefficients could be computed for each energy level. The resulting set of MARVEL levels is called active as when new experimental measurements become available the same evaluation, adjustment, and inversion procedure should be repeated in order to obtain more dependable energy levels and uncertainties. MARVEL is tested on the example of the H-2 O-17 isotopologue of water and a list of 2736 dependable energy levels, based on 8369 transitions, has been obtained. (c) 2007 Elsevier Inc. All rights reserved
Katabolismus des Molybdän-Cofaktors - Identifikation der endogenen Thiopterin-Methyltransferase
The effect of loving kindness meditation and student teachers stress and empathy
Teachers face increasing demands in the twenty-first century as they engage with students, administrators, coworkers, staff, and parents. High demands and stressors may generate feelings of emotional exhaustion in educators. If left ignored or untreated the emotional exhaustion may eventually lead to burnout and impairment. This prospectus highlights a study designed to explore a preventative option to mitigate the experience of stress felt by student teachers through a structured, guided mindfulness training practice: loving kindness meditation
A note on how NK landscapes work
Abstract
The NK landscape methodology has been used by much research in strategy and organizations, and the concept of “landscape” has become a popular business idea. Despite such popularity, exactly what NK landscapes are and how they work is typically obscure to all but a small specialist audience. This technical note clarifies the NK landscape methodology by explaining how an NK landscape is computed. This note also discusses ways in which NK landscapes are represented and used in research. The aim of this note is enabling more researchers to engage more deeply with the work that relies on the landscape concept.https://deepblue.lib.umich.edu/bitstream/2027.42/146753/1/41469_2018_Article_39.pd
Identifying and Correcting an Edge-Fattened Area Generated by Stereo-Matching Techniques
This publication describes an image-boundary manager used in an image-capture device. The image-boundary manager uses a low-complexity algorithm to compute an edge-fattened area of a foreground object included in an image of a scene generated by the image-capture device. After computing the edge-fattened area of the foreground object, the image-capture manager assigns correct depth values to the edge-fattened area such that the image-capture device renders the foreground object, in a modified image of the scene, accurately and without the edge-fattened area
High accuracy calculations of the rotation-vibration spectrum of H
Calculation of the rotation-vibration spectrum of H3+, as well as of its
deuterated isotopologues, with near-spectroscopic accuracy requires the
development of sophisticated theoretical models, methods, and codes. The
present paper reviews the state-of-the-art in these fields. Computation of
rovibrational states on a given potential energy surface (PES) has now become
standard for triatomic molecules, at least up to intermediate energies, due to
developments achieved by the present authors and others. However, highly
accurate Born--Oppenheimer energies leading to highly accurate PESs are not
accessible even for this two-electron system using conventional electronic
structure procedures e.g., configuration-interaction or coupled-cluster
techniques with extrapolation to the complete basis set limit). For this
purpose highly specialized techniques must be used, e.g., those employing
explicitly correlated Gaussians and nonlinear parameter optimizations. It has
also become evident that a very dense grid of \ai\ points is required to obtain
reliable representations of the computed points extending from the minimum to
the asymptotic limits. Furthermore, adiabatic, relativistic, and QED correction
terms need to be considered to achieve near-spectroscopic accuracy during
calculation of the rotation-vibration spectrum of H3+. The remaining and most
intractable problem is then the treatment of the effects of non-adiabatic
coupling on the rovibrational energies, which, in the worst cases, may lead to
corrections on the order of several \cm. A promising way of handling this
difficulty is the further development of effective, motion- or even
coordinate-dependent, masses and mass surfaces. Finally, the unresolved
challenge of how to describe and elucidate the experimental pre-dissociation
spectra of H and its isotopologues is discussed.Comment: Topical review to be published in J Phys B: At Mol Opt Phy
How Much to Copy? Determinants of Effective Imitation Breadth
It is a common and frequently implicit assumption in the literature on knowledge transfer and organizational learning that imitating practices from high-performing firms has a positive impact on the imitating firm. Although a large body of research has identified obstacles to successful imitation, not much is known about what breadth of imitation is most effective. In this paper, we use a simulation model to explore how context and firm similarity, interdependence among practices, context and firm similarity, and time horizon interact in nontrivial ways to determine the payoffs that arise from different breadths of imitation. The results of the model allow us to qualify and refine predictions of the extant literature on imitation. In particular, the results shed light on the conditions under which increases in imitation breadth, and hence investments that facilitate the faithful copying of more practices, are valuable. In addition, the results of the model highlight that imitation can serve two different functions—mimicking high performers, and generating search by dislodging a firm from its current set of practices—each requiring different organizational routines for its successful implementation
On the use of reduced-density matrices for the semi-automatic assignment of vibrational states
The use of one- and two-mode reduced-density matrices (RDM), and , respectively, and in particular the use of their diagonal elements, and , is suggested for the assignment of normal-mode-like quantum numbers to variationally computed vibrational wave functions of semirigid molecules when the computation is based on a nuclear-motion Hamiltonian expressed in curvilinear internal coordinates . The use of RDMs for the semi-automatic assignment of vibrational states is tested on the HO molecule, whereby about the first 250 states, in the energy range of 0-25,000cm(-1), are assigned. The proposed semi-automatic assignment procedure takes advantage of the fact that (a) for semirigid molecules it is often possible to define internal coordinates which mimick normal coordinates defined by the harmonic counterparts of the anharmonic vibrations, (b) overlaps between already assigned and yet unassigned RDMs provide outstanding and often unambiguous suggestions for the quantum numbers, and (c) an energy-decomposition scheme helps to decide among possible assignment possibilities suggested by the computed density overlaps. [GRAPHICS]
Experimental energy levels and partition function of the C molecule
The carbon dimer, the C molecule, is ubiquitous in astronomical
environments. Experimental-quality rovibronic energy levels are reported for
C, based on rovibronic transitions measured for and among its
singlet, triplet, and quintet electronic states, reported in 42 publications.
The determination utilizes the Measured Active Rotational-Vibrational Energy
Levels (MARVEL) technique. The 23,343 transitions measured experimentally and
validated within this study determine 5,699 rovibronic energy levels, 1,325,
4,309, and 65 levels for the singlet, triplet, and quintet states investigated,
respectively. The MARVEL analysis provides rovibronic energies for six singlet,
six triplet, and two quintet electronic states. For example, the lowest
measurable energy level of the \astate\ state, corresponding to the total
angular momentum quantum number and the spin-multiplet component, is
603.817(5) \cm. This well-determined energy difference should facilitate
observations of singlet--triplet intercombination lines which are thought to
occur in the interstellar medium and comets. The large number of highly
accurate and clearly labeled transitions that can be derived by combining
MARVEL energy levels with computed temperature-dependent intensities should
help a number of astrophysical observations as well as corresponding laboratory
measurements. The experimental rovibronic energy levels, augmented, where
needed, with {\it ab initio} variational ones based on empirically adjusted and
spin-orbit coupled potential energy curves obtained using the \Duo\ code, are
used to obtain a highly accurate partition function, and related thermodynamic
data, for C up to 4,000 K.Comment: ApJ Supplements (in press), 48 page
- …