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21.
Leoní A. Barrios Dr. David Aguilà Olivier Roubeau Dr. Patrick Gamez Dr. Jordi Ribas‐Ariño Dr. Simon J. Teat Dr. Guillem Aromí Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(42):11235-11243
The ligand 1,3‐bis[3‐oxo‐3‐(2‐hydroxyphenyl)propionyl]benzene (H4L), designed to align transition metals into tetranuclear linear molecules, reacts with MII salts (M=Ni, Co, Cu) to yield complexes with the expected [MM???MM] topology. The novel complexes [Co4L2(py)6] ( 2 ; py=pyridine) and [Na(py)2][Cu4L2(py)4](ClO4) ( 3 ) have been crystallographically characterised. The metal sites in complexes 2 and 3 , together with previously characterised [Ni4L2(py)6] ( 1 ), favour different coordination geometries. These have been exploited for the deliberate synthesis of the heterometallic complex [Cu2Ni2L2(py)6] ( 4 ). Complexes 1 , 2 , 3 and 4 exhibit antiferromagnetic interactions between pairs of metals within each cluster, leading to S=0 spin ground states, except for the latter cluster, which features two quasi‐independent S=1/2 moieties within the molecule. Complex 4 gathers the structural and physical conditions, thus allowing it to be considered as prototype of a two‐qbit quantum gate. 相似文献
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An updated version of the computational package SIMPRE that uses the standard conventions for Stevens crystal field parameters 下载免费PDF全文
José J. Baldoví Juan M. Clemente‐Juan Eugenio Coronado Alejandro Gaita‐Ariño Andrew Palii 《Journal of computational chemistry》2014,35(26):1930-1934
The crystal field approach used by SIMPRE is analyzed, verifying the exactness of the results concerning energy levels and magnetic properties calculated by the package. To coincide with the prevailing conventions, we reformulate the presentation of the crystal field parameters, so that the results are now, also from a formal point of view, strictly correct. New calculations are presented to test the influence of neglecting the excited J states, a common but critical approximation employed by SIMPRE. For that, we examine the case of Er(trensal) complex (H3trensal = 2,2′,2″‐tris(salicylideneimino)triethylamine) where the influence of this approximation is found to be minimal. A patched version of the code, SIMPRE 1.1, and an updated version of the user manual are now available. Finally, we comment on “Software package SIMPRE – revisited,” which apparently revisits a software package without inspecting or using the code. © 2014 Wiley Periodicals, Inc. 相似文献
24.
Simon Ludwanowski Dr. Meral Ari Karsten Parison Somar Kalthoum Paula Straub Nils Pompe Prof. Dr. Stefan Weber Priv.-Doz. Dr. Michael Walter Prof. Dr. Andreas Walther 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13203-13212
Arylazopyrazoles are an emerging class of photoswitches with redshifted switching wavelength, high photostationary states, long thermal half-lives and facile synthetic access. Understanding pathways for a simple modulation of the thermal half-lives, while keeping other parameters of interest constant, is an important aspect for out-of-equilibrium systems design and applications. Here, it is demonstrated that the thermal half-life of a water-soluble PEG-tethered arylazo-bis(o-methylated)pyrazole (AAP) can be tuned by more than five orders of magnitude using simple pH adjustment, which is beyond the tunability of azobenzenes. The mechanism of thermal relaxation is investigated by thorough spectroscopic analyses and density functional theory (DFT) calculations. Finally, the concepts of a tunable half-life are transferred from the molecular scale to the material scale. Based on the photochromic characteristics of E- and Z-AAP, transient information storage is showcased in form of light-written patterns inside films cast from different pH, which in turn leads to different times of storage. With respect to prospective precisely tunable materials and time-programmed out-of-equilibrium systems, an externally tunable half-life is likely advantageous over changing the entire system by the replacement of the photoswitch. 相似文献
25.
The absorption spectrum of CO2 in the 4.82-μm region has been observed with a high-resolution spectrometer. The (1110, 0310)I-0000 transition and the “hot” transitions (1220, 0420)I-0110 and (2000, 0400)I-0110 have been calibrated. The effective rotational constants of the upper levels have been deduced with good accuracy. 相似文献
26.
We consider the infinite horizon risk-sensitive problem for nondegenerate diffusions with a compact action space, and controlled through the drift. We only impose a structural assumption on the running cost function, namely near-monotonicity, and show that there always exists a solution to the risk-sensitive Hamilton–Jacobi–Bellman (HJB) equation, and that any minimizer in the Hamiltonian is optimal in the class of stationary Markov controls. Under the additional hypothesis that the coefficients of the diffusion are bounded, and satisfy a condition that limits (even though it still allows) transient behavior, we show that any minimizer in the Hamiltonian is optimal in the class of all admissible controls. In addition, we present a sufficient condition, under which the solution of the HJB is unique (up to a multiplicative constant), and establish the usual verification result. We also present some new results concerning the multiplicative Poisson equation for elliptic operators in . 相似文献
27.
High bit rates optical communication systems pose the challenge of their tolerance to linear and non-linear fiber impairments. Coherent optical receivers using digital signal processing techniques can mitigate the fiber impairments in the optical transmission system, including the chromatic dispersion equalization with digital filters. In this paper, an adaptive finite impulse response filter employing normalized least mean square algorithm is developed for compensating the chromatic dispersion in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent communication system, which is established in the VPI simulation platform. The principle of the adaptive normalized least mean square algorithm for signal equalization is analyzed theoretically, and at the meanwhile, the taps number and the tap weights in the adaptive finite impulse response filter for compensating a certain fiber chromatic dispersion are also investigated by numerical simulation. The chromatic dispersion compensation performance of the adaptive filter is analyzed by evaluating the behavior of the bit-error-rate versus the optical signal-to-noise ratio, and the compensation results are also compared with other present digital filters. 相似文献
28.
We study the magneto-optic (MO) Faraday rotation in a two-dimensional square-lattice photonic crystal with a central MO defect layer in the optical wavelength range. We show that when a TM plane wave is incident upon a photonic crystal, an enhancement of Faraday rotation takes place in a region where a resonance peak appears in the photonic bandgap. In this region the mode conversion is high. 相似文献
29.
We study a model of a queueing system with two complementary products/services. In our model, there is one M/M/1 system and another facility that provides instantaneous service. The two services are complementary and the customer has no benefit from obtaining just one of them. We investigate the model under various price structures and ownership assumptions.AMS subject classification: 90B22, 91A10The authors are equal in their contribution to this paper. This paper is submitted by the first author to the Tokyo Institute of Technology as partial fulfillment of the requirements for the Ph.D. program in the Department of Value and Decision Sciences, and the order of names was chosen in compliance with program conditions. This research was supported by the Israel Science Foundation (grant No. 237/02). 相似文献
30.
This paper considers the weighted extended b-splines as basis function for finite element method in electromagnetics and compares with the standard finite element method applied to the two-point boundary value problems with different boundary conditions. This new approach, which provides more accurate results than standard finite element method, is presented to compare other numerical techniques and applied to one-dimensional electromagnetic problems. Computed results are compared with other numerical results in literature. 相似文献