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111.
Decleva P Fronzoni G Stener M de Simone M Coreno M Green JC Hazari N Plekan O 《Physical review letters》2005,95(26):263401
Photoemission from the two outermost ionizations [highest occupied molecular orbitals (HOMO and HOMO-1)] of Mg(eta(5)-C(5)H(5))(2) has been studied with synchrotron radiation in the gas phase. Strong oscillations in the HOMO-1/HOMO ratio, qualitatively similar to those well-known for fullerenes, are found. Excellent agreement with the experimental ratio is provided by accurate cross section calculations both at the density-functional theory and time-dependent density-functional theory level, indicating that a many electron response has a minor role for this effect. A comparison with the calculated values for other metal sandwich compounds indicate that the presence of oscillations is a widespread phenomenon, and a potential source of interesting information on the structural and electronic properties of the target molecule. 相似文献
112.
Aubin C Bernard C Detar C Di Pierro M Freeland ED Gottlieb S Heller UM Hetrick JE El-Khadra AX Kronfeld AS Levkova L Mackenzie PB Menscher D Maresca F Nobes M Okamoto M Renner D Simone J Sugar R Toussaint D Trottier HD;Fermilab Lattice Collaboration;MILC Collaboration;HPQCD Collaboration 《Physical review letters》2005,95(12):122002
We present the first lattice QCD calculation with realistic sea quark content of the D+-meson decay constant f(D+). We use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f(D+)=201+/-3+/-17 MeV, where the errors are statistical and a combination of systematic errors. We also obtain f(Ds)=249+/-3+/-16 MeV for the Ds meson. 相似文献
113.
We present a compact optical design for a multireference Shack-Hartmann-based wavefront sensor (WFS) for multiconjugate adaptive optical systems. The key component of this WFS design is a field lenslet array that separates the exit pupil images in the sensing plane for all reference sources. An analytical method for WFS optical design is presented, and the optimal strategy for selecting optical components from a discrete set is outlined. The feasibility of the WFS design has been demonstrated for a prototype WFS system in a laboratory setup with five reference sources and two deformable mirrors representing a wavefront-distorting medium. 相似文献
114.
Ceccherini S 《Optics letters》2005,30(19):2554-2556
In the retrieval of vertical profiles of atmospheric constituents, regularization methods are frequently used to improve the conditioning of the solution. The regularization reduces the retrieval errors and causes the vertical resolution to deteriorate. One obtains a trade-off by tuning the strength of the regularization by way of a regularization parameter. A new analytical method for determining the regularization parameter is presented. This method is suitable for operational retrievals, for which an unattended procedure is required. The performance of the new method is compared with that of the L-curve method, and the results show that a better trade-off between retrieval errors and vertical resolution is obtained. 相似文献
115.
Thermal diffusion forced Rayleigh scattering results on thermal diffusion of poly(ethylene oxide) (PEO) in ethanol/water mixtures are presented. In water-rich solvent mixtures, PEO is found to migrate towards regions of lower temperature. This is typical for polymer solutions and corresponds to a positive Soret coefficient of PEO. In solvent mixtures with low water content, however, the polymer is found to migrate towards higher temperatures, corresponding to a negative Soret coefficient of PEO in ethanol-rich solutions. To our knowledge, this is the first observed sign change of the Soret coefficient of a polymer in solution. We also present a simple lattice model for the polymer solvent system and calculate Soret coefficients with statistical mechanics methods. The calculated values agree qualitatively with the experimental results. 相似文献
116.
117.
Mauro L. Bonardi Flavia Groppi Simone Manenti Elisa Persico Luigi Gini Kamel Abbas Uwe Holzwarth Federica Simonelli Zeev B. Alfassi 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):1-7
Very high specific activity (AS) 186gRe could be produced by either proton or deuteron cyclotron irradiation on highly enriched 186W target in no-carrier-added (NCA) form, leading to a AS very close to the theoretical carrier free (CF) value of 6.88 GBq μg−1. Thick Target Yields (TTYs), obtained irradiating both thick metal W targets of natural isotopic composition and highly enriched
powdered 186W targets, were measured at different particles energies taking into account high accuracy and precision. The evaluation of
radionuclidic purities of 186gRe obtained activating highly enriched 186W by both p and d were also carried out and accurately compared. The thin-target excitation functions for all Re (A = 181,
182, 183, 184, 186 and their metastable levels), and W and Ta coproduced radionuclides will be presented elsewhere in deep
details. 相似文献
118.
To get a true hybrid framework for taking operational decisions from data, we extend the Algorithmic Inference approach to the Granular Computing paradigm. The key idea is that whether or not we need to make decisions instead of mere computations depends on the fact that collected data are not sufficiently definite; rather, they are representative of whole sets of data that could be virtually observed, and we need to manage this indeterminacy. The distinguishing feature is that we face indeterminacy exactly where it affects the quality of the decision. This gives rise to a family of inference algorithms which can be tailored to many specific decisional problems that are generally solved only in approximate ways. In the paper we discuss the bases of the paradigm and provide some examples of its implementation. 相似文献
119.
Pietro Franceschi Roland Thissen Odile Dutuit Christian Alcaraz Heloise Soldi-Lose Davide Bassi Daniela Ascenzi Paolo Tosi Jan Zabka Zdenek Herman Marcello Coreno Monica de Simone 《International journal of mass spectrometry》2009,280(1-3):119
The long-lived excited states of doubly charged rare gases can markedly affect their reactivity. In this paper we demonstrate the presence of strong state-specific effects in the charge exchange of Ar2+ (3P, 1D and 1S) with several neutral targets (He, Ne, Kr, Xe, D2, and CH4). State sensitive measurements have been performed by producing the different Ar2+ electronic states via tunable synchrotron radiation (Elettra-Trieste, Italy and SuperACO-Orsay, France). From the product ion yield data of charge transfer, state-selected total cross-sections have been deduced. Using the state-specific reactivity of Ar2+ towards different neutral targets, it has been possible to extract the photon-energy-dependent production branching of the three doubly charged states and to investigate the autoionization dynamics of neutral or singly charged Ar in the vicinity of the double ionization threshold. 相似文献
120.