Search results for "iTED"
showing 10 items of 2408 documents
Theoretical Study of the 15- and 17-Electron Structures of Cyclopentadienylchromium(III) and Cyclopentadienylmolybdenum(III) Complexes. Dichloride an…
1997
International audience; The structure and the energetics of the model systems CpMX2(PH3) + PH3 ⇄ CpMX2(PH3)2 (Cp = cyclopentadienyl; M = Cr, Mo; X = Cl, CH3) are studied by performing Møller−Plesset second order (MP2) and density functional theory (DFT) calculations. Extended basis sets are employed in the geometry optimizations. The results indicate that the structural preference can be traced back to the competition between electron pairing stabilization and M−P bond dissociation energy along the spin doublet surface. At all levels of calculation, the energy splitting, a measure of the cost of pairing the electron during the promotion process from the quartet ground state to the excited d…
Transient absorption studies of the Ru(dcbpy)2(NCS)2 excited state and the dye cation on nanocrystalline TiO2 film
2001
We have measured dynamics of the Ru(dcbpy)2(NCS)2 [dcbpy = 4,4′-dicarboxy-2,2′-bipyridine] excited state and the dye cation on nanocrystalline TiO2 film in the wavelength region 700–900 nm. The dye in ethanol solution and Ru(dcbpy)2(NCS)2 sensitized nanocrystalline Al2O3 films were used as non-injecting reference samples for excited state identification. For TiO2/Ru(dcbpy)2(NCS)2 film the `reactant' decay and `product' formation kinetics observed at different probe wavelengths showed that the resolved transient absorption picosecond components (1.1±0.2), (12±2) and (100±5) ps are related to electron injection from the excited states of the dye to the semiconductor TiO2.
Electron Transfer from the Singlet and Triplet Excited States of Ru(dcbpy)2(NCS)2into Nanocrystalline TiO2Thin Films
2002
Time-resolved absorption spectroscopy was used to study the femtosecond and picosecond time scale electron injection from the excited singlet and triplet states of Ru(dcbpY)(2)(NCS)(2) (RuN3) into titanium dioxide (TiO2) nanocrystalline particle film in acetonitrile. The fastest resolved time constant of similar to30 fs was shown to reflect a sum of two parallel ultrafast processes, nonergodic electron transfer (ET) from the initially excited singlet state of RuN3 to the conduction band of TiO2 and intersystem crossing (ISC). The branching ratio of 1.5 between the two competing processes gives rate constants of 1/50 fs(-1) for ET and 1/75 fs(-1) for ISC. Following the ultrafast processes, a…
A two-scale approach to electron correlation in multiconfigurational perturbation theory.
2014
We present a new approach for the calculation of dynamic electron correlation effects in large molecular systems using multiconfigurational second-order perturbation theory (CASPT2). The method is restricted to cases where partitioning of the molecular system into an active site and an environment is meaningful. Only dynamic correlation effects derived from orbitals extending over the active site are included at the CASPT2 level of theory, whereas the correlation effects of the environment are retrieved at lower computational costs. For sufficiently large systems, the small errors introduced by this approximation are contrasted by the substantial savings in both storage and computational de…
Photoconductivity & photoelectron emission of LiGaO2 crystal excited in intrinsic absorption range
2019
This research is funded by the Latvian Council of Science, project “Research of luminescence mechanisms and dosimeter properties in prospective nitrides and oxides using TL and OSL methods], project No. lzp-2018/0361.
I due volti dell'America nelle novelle di Luigi Pirandello
2018
Di fronte al fenomeno emigratorio che ha condotto verso le Americhe migliaia di Italiani, gli intellettuali si sono divisi tra posizioni contrastanti alle quali ha fatto eco, in ambito letterario, un atteggiamento altrettanto contraddittorio. L’America, e in particolar modo gli Stati Uniti, incarnava, nel momento della giovanissima Italia liberale, la modernità compiuta e realizzata che faceva da contraltare ad un’Europa ancorata alla storia, alle tradizioni e ai valori culturali. Fra gli scrittori che sentirono il bisogno di raccontare questo macro-fenomeno sociale è Luigi Pirandello che, nelle sue novelle, afronta il tema da due punti di vista differenti scanditi cronologicamente sulla ba…
Work-related and personal predictors of COVID-19 transmission: evidence from the UK and USA
2021
ObjectiveTo develop evidence of work-related and personal predictors of COVID-19 transmission.Setting and respondentsData are drawn from a population survey of individuals in the USA and UK conducted in June 2020.Background methodsRegression models are estimated for 1467 individuals in which reported evidence of infection depends on work-related factors as well as a variety of personal controls.ResultsThe following themes emerge from the analysis. First, a range of work-related factors are significant sources of variation in COVID-19 infection as indicated by self-reports of medical diagnosis or symptoms. This includes evidence about workplace types, consultation about safety and union memb…
Job Insecurity in Nursing: A Bibliometric Analysis
2021
Nurses are a key workforce in the international health system, and as such maintaining optimal working conditions is critical for preserving their well-being and good performance. One of the psychosocial risks that can have a major impact on them is job insecurity. This study aimed to carry out a bibliometric analysis, mapping job insecurity in 128 articles in nursing, and to determine the most important findings in the literature. The search was conducted in the Web of Science Core Collection database using the Science Citation Index (SCI)-Expanded and Social Sciences Citation Index (SSCI) indexes on 6 March 2020. This field of discipline has recently been established and has experienced s…
Near-infrared emissive bacteriochlorin-diketopyrrolopyrrole triads: Synthesis and photophysical properties
2019
International audience; The synthesis of unprecedented energy transfer triads containing a near-infrared (NIR) emissive bacteriochlorin subunit and two diketopyrrolopyrrole (DPP) moieties linked to each other via ethynyl or zero-carbon spacers is presented. Their optical and fluorescence properties were determined in CHCl3 and toluene. These photophysical measurements highlight the ability of DPP scaffold to act as an effective energy donor, which once excited in the range 450-550 nm resulting nearly exclusively NIR emission of hydroporphyrin (ETE > 96%). Since DPP dyes are valuable structurally tunable fluorophores that may be used in the construction of high-performance multicomponent pho…
Is naturalistic driving research possible with highly instrumented cars? Lessons learnt in three research centres.
2011
This paper provides an overview of the experiences using Highly Instrumented Cars (HICs) in three research Centres across Europe; Spain, the UK and Greece. The data collection capability of each car is described and an overview presented relating to the relationship between the level of instrumentation and the research possible. A discussion then follows which considers the advantages and disadvantages of using HICs for ND research. This includes the obtrusive nature of the data collection equipment, the cost of equipping the vehicles with sophisticated Data Acquisition Systems (DAS) and the challenges for data storage and analysis particularly with respect to video data. It is concluded th…