43 research outputs found
Direct measurement of the fine-structure interval and g_J factors of singly ionized atomic carbon by laser magnetic resonance
We present the results of laser magnetic resonance measurements performed on the ground ^2P state of singly
ionized atomic carbon (C_II). The 2^P_(3/2) ← ^2P_(1/2) fine-structure intervals of both ^(12)C^+ and ^(13)C^+ have been determined with a precision of approximately 1 ppm, and the g_J factors to approximately one part in 10^4.
Specifically, we find that g_(J=(1/2)) = 0.66576(11) and g_(J=(3/2)) = 1.33412(11), while for ^(12)C^+ ΔE_0(^2P_(3/2) ← ^2P_(1/2))= 1900536.9(1.3) MHz, with ΔE_0(^2P_(3/2) ← ^2P_(1/2)) = 1900545.8(2.1) and ΔE(^2P(3/2) ← ^2P_(1/2), F = 2 ← 1) = 1900466.1(2.3) MHz in ^(13)C^+. The highly precise values of the ^(12)C_II and ^(13)C_II fine-structure intervals verify the already secure far-infrared astronomical identification of C^+ and should allow the interstellar (^(12)C / ^(13)C) ratio to
be unambiguously determined in a number of environments
Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions
Background:
Due to the chronic disease burden on society, there is a need for preventive public health interventions to stimulate society towards a healthier lifestyle. To deal with the complex variability between individual lifestyles and settings, collaborating with end-users to develop interventions tailored to their unique circumstances has been suggested as a potential way to improve effectiveness and adherence. Co-creation of public health interventions using participatory methodologies has shown promise but lacks a framework to make this process systematic. The aim of this paper was to identify and set key principles and recommendations for systematically applying participatory methodologies to co-create and evaluate public health interventions.
Methods:
These principles and recommendations were derived using an iterative reflection process, combining key learning from published literature in addition to critical reflection on three case studies conducted by research groups in three European institutions, all of whom have expertise in co-creating public health interventions using different participatory methodologies.
Results:
Key principles and recommendations for using participatory methodologies in public health intervention co-creation are presented for the stages of: Planning (framing the aim of the study and identifying the appropriate sampling strategy); Conducting (defining the procedure, in addition to manifesting ownership); Evaluating (the process and the effectiveness) and Reporting (providing guidelines to report the findings). Three scaling models are proposed to demonstrate how to scale locally developed interventions to a population level.
Conclusions:
These recommendations aim to facilitate public health intervention co-creation and evaluation utilising participatory methodologies by ensuring the process is systematic and reproducible
1 Evaluation Policy: An Introduction and Overview
Evaluation policy is of considerable importance, especially in relation to the limite
Dipole moment analysis of excited van der Waals vibrational states of ArH35Cl
The far-infrared laser electric resonance spectra of the prototypical atom—diatom complex ArH35Cl are analyzed using improved zero-field molecular constants, yielding accurate permanent and transition dipole moments for the three lowest excited van der Waals vibrational states. The constants are obtained from a multistate fit to previous microwave, far-infrared laser electric resonance, and far-infrared tunable laser spectra, as well as new far-infrared measurements of the Sigma -stretch state, which are reported here. The signs of the dipole moments and Coriolis coefficients establish the relative orientations of the HCl subunit in these states. The fit is found to converge only if these signs correspond to the HCl pointing in opposite directions along the a inertial axis in the Sigma -stretch and Sigma -bend states. A weak preference, near the experimental error limit, is found for the Ar—Cl—H average angle in the Pi -bend state to be greater than 90°, contrary to expectation. For the best fit, we obtain the a-axis dipole moment components -0.5413(11) D ( Sigma bend), -0.263 45(29) D ( Pi bend), and 0.6754(36) D ( Sigma -stretch); and the b-axis components 0.365(12) D ( Pi and Sigma -bend) and -0.0465(43) D ( Pi and Sigma stretches), where the signs of the Coriolis coefficients and µa for the Sigma stretch have been arbitrarily fixed positive. For the expected Pi -bend configuration, with the Ar—Cl—H angle less than 90°, the magnitudes along the a axis change only slightly, but the b-axis components become 0.149(12) and -0.1403(64) D for the Pi — Sigma -bend and Pi — Sigma -stretch interactions, respectively
MILLIMETER-WAVE SPECTROSCOPY OF THE HCCCO AND DCCCO RADICAS
1. Z.A TomaxiEcA and G.E. Suxeria, J. Phys. Chem. 95 , 6905-6908(1991). 2. R.D. Brown, R. Champion, P.S. Elmes, and P.D. Godfrey, J. Am. Chem. Soc. 107 , 4109-4112(1985). 3. Y. Endo and E. Hirota, J. Chem. Phys. 86 , 4319-4326 (1987).Author Institution: Harvard-Smitsonian Center for Astrophysics, and Department of Chemistry, Harvard University; Herzberg Institute of Astrophysics, National Research Council; Division of Applied Sciences, Harvard University; Division of Applied Sciences, Harvard-Smithsonian Center for AstrophysicsOver 300 rotational transitions of the free radicals HCCCO AND DCCCO between 80 and 400 GHz have been observed by millimeter-wave glow discharge spectroscopy. Analysis of ground state energy levels of and using the S-reduced asymmetric top effective Humiltonian, including treatment of a reasonant spin-rotation perturbation, confirms the qualitative ab initio result that HCCCO and DCCCO have highly prolate bent chain . However, the rotational constants are reproduced with better precision by removing one hydrogen from the experimental implying that HCCCO is more bent than predicted. The rotation and spin-rotation constants indicate that the Renner-Teller effect in this system is stronger than in and the high degree of distortion is evidence for substantial coupling between bending vibration and rotation about the a-axis. Analysis of the moments of inertia of the two isotopomers yield the a-- and b--axis coordinates of the hydrogen atom and a -- and b--axis moments of inertia for the CCCO subunit in the vibrationally averaged structure
OBSERVATION OF THE LOWEST AND BENDING STATES OF ARHCN BY MOLECULAR BEAM ELECTRIC RESONANCE
1. G.T. Fraser, R.D. Suenram, and L.H. Coudert, J. Chem. Phys. 90, 6077 (1989). 2. K.R. Leopold, G. T. Fraser, F.J. Lin, D.D. Nelson, JR., and W. Klemperer, J. Chem. Phys. 81, 4922 (1984). 3. S.W. Reeve, M.A. Dvorak, D.W. Firth, and K.R. Leopold, Chem. Phys. Lett. 181, 259 (1991).Author Institution: Department of Chemistry, Harvard University; Division of Applied Science, Harvard UniversityA Fraser--type was used to observe the lowest excited and states of the van der Waals bending mode of ArHCN. Direct transitions from the ground vibrational state were observed. The molecular carrier and lower state rotational quantum numbers were confirmed by double resonance with known ground state rotational transitions of the For the state, the , and transitions were observed, and for the state, and were observed, - double resonance signals were also obtained. The spectral resolution is about 30 kHz, which allowed the quadrupole hyperfine structure and Stark effect to be measured for each of the excited states. The vibrational states are strongly coupled by rotation. The molecular constants are (in MHZ) ; ; (Coriolis coupling and . The rotational constant of the ground state is 1609.832 MHz. The rotational constants given for the excited states are the deperturbed ``geometric” ones. The similarity of and is surprising, as is the closeness of the estimated average angle for the two states
PRECISE MEASUREMENT OF FINE STRUCTURE INTERVALS IN ATOMIC IONS BY LASER MAGNETIC RESONANCE SPECTROSCOPY: AND
Address of Cooksy, Hovde, Blake, and Saykally: Department of Chemistry, University of California, Berkeley, CA 94720Author Institution:Direct observation of the fine structure transition in and the transition in by far-infrared laser magnetic resonance spectroscopy has led to the precise evaluation of these fine structure splittings and corresponding -factors and hyperfine parameters. These values are expected to facilitate the observation and analysis of these transitions in the interstellar medium
TUNABLE FAR INFRARED LASER SPECTROSCOPY OF JET-COOLED CARBON CLUSTERS: THE BENDING VIBRATION OF
Author Institution: Department of Chemistry, University of California, and Materials and chemical Sciences Division Lawrence Barkeley LaboratorySeven rovibrational transitions of the fundamental bending band of habe been measured with high precision using a tunable far-infrared laser spectrometer. The molecules were produced by laser vaporization of a graphite rod and cooled in a supersonic expansion. This is the first determination of the astronomically inportant fundamental frequency near intersteller medium with far-infrared astronomy
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Finding the proton in a key intermediate of anti-Markovnikov alkyne hydration by a bifunctional catalyst
The secondary structure of a bifunctional catalyst positions a crucial reactive proton in the final intermediate of anti-Markovnikov alkyne hydration to give an aldehyde. NMR coupling and isotopic labeling studies elucidate the location of this proton and its involvement in hydrogen bonding