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41.
Diana M. Mate David Gonzalez-Perez Magnus Falk Roman Kittl Marcos Pita Antonio L. De Lacey Roland Ludwig Sergey Shleev Miguel Alcalde 《Chemistry & biology》2013,20(2):223-231
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42.
A. M. Alcalde Qu Fanyao G. E. Marques 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):228
We have calculated spin-relaxation rates in parabolic quantum dots due to the phonon modulation of the spin–orbit interaction in the presence of an external magnetic field. Both deformation potential and piezoelectric electron–phonon coupling mechanisms are included within the Pavlov–Firsov spin–phonon Hamiltonian. Our results have demonstrated that, in narrow gap materials, the electron–phonon deformation potential and piezoelectric coupling give comparable contributions to spin-relaxation processes. For large dots, the deformation potential interaction becomes dominant. This behavior is not observed in wide or intermediate gap semiconductors, where the piezoelectric coupling, in general, governs the spin-relaxation processes. We have also demonstrated that spin-relaxation rates are particularly sensitive to the Landé g-factor. 相似文献
43.
S. J. Prado C. Trallero-Giner V. Lpez-Richard A. M. Alcalde G. E. Marques 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):286
We present a systematic theoretical study, based on the Kane–Weiler 8×8 k·p model, of the linear Zeeman splitting introduced by the interaction between the angular momentum and the magnetic field which can give a measure of the non-linear Zeeman effect associated with interband coupling and diamagnetic contributions. The conduction and valence bands g-factors are calculated for InSb spherical and semi-spherical quantum dots. The calculations of the g-factors showed an almost linear dependence, for the ground state, on the magnetic field. We have also found that the strong magnetic field dependence as well as the dependence on the dot size of the effective spin splitting can be unambiguously attributed to the strength of the inter-level mixing. 相似文献
44.
David Aguilà Dr. Leoní A. Barrios Verónica Velasco Leticia Arnedo Dr. Núria Aliaga‐Alcalde Dr. Melita Menelaou Dr. Simon J. Teat Dr. Olivier Roubeau Dr. Fernando Luis Dr. Guillem Aromí 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):5881-5891
A complete isostructural series of dinuclear asymmetric lanthanide complexes has been synthesized by using the ligand 6‐[3‐oxo‐3‐(2‐hydroxyphenyl)propionyl]pyridine‐2‐carboxylic acid (H3 L ). All complexes have the formula [Ln2(H L )2(H2 L )(NO3)(py)(H2O)] (Ln=La ( 1 ), Ce ( 2 ), Pr ( 3 ), Nd ( 4 ), Sm ( 5 ), Eu ( 6 ), Gd ( 7 ), Tb ( 8 ), Dy ( 9 ), Ho ( 10 ), Er ( 11 ), Tm ( 12 ), Yb ( 13 ), Lu ( 14 ), Y ( 15 ); py=pyridine). Complexes of La to Yb and Y have been crystallographically characterized to reveal that the two metal ions are encapsulated within two distinct coordination environments of differing size. Whereas one site maintains the coordination number (nine) through the whole series, the other one increases from nine to ten owing to a change in the coordination mode of an NO3? ligand. This series offers a unique opportunity to study in detail the lanthanide contraction within complexes of more than one metal. This analysis shows that various representative parameters proportional to this contraction follow a quadratic decay as a function of the number n of f electrons. Slater’s model for the atomic radii has been used to extract, from these decays, the shielding constant of 4f electrons. The average of O???O distances within the coordination polyhedra shared by both metals and of the Ln???Ln separations follow also a quadratic decay, therefore showing that such dependence holds also for parameters that receive the contribution of two lanthanide ions simultaneously. The magnetic behavior has been studied for all nondiamagnetic complexes. It reveals the effect of the spin–orbit coupling and a weak antiferromagnetic interaction between both metals. Photoluminescent studies of all the complexes in the series reveal a single broad emission band in the visible region, which is related to the coordinated ligand. On the other hand, the Nd, Er, and Yb complexes show features in the near‐IR region due to metal‐based transitions. 相似文献
45.
Water‐Soluble Manganese Inorganic Polymers: The Role of Carborane Clusters and Producing Large Structural Adjustments from Minor Molecular Changes
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Dr. Mònica Fontanet Dr. Montserrat Rodríguez Xavier Fontrodona Dr. Isabel Romero Dr. Francesc Teixidor Dr. Clara Viñas Dr. Núria Aliaga‐Alcalde Dr. Pavel Matějíček 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(43):13993-14003
The reaction of two different carboranylcarboxylate ligands, 1‐CH3‐2‐CO2H‐1,2‐closo‐C2B10H10 or 1‐CO2H‐1,2‐closo‐C2B10H11, with MnCO3 in water leads to polymeric compounds 1 a and 1 b . Both compounds have been characterized by analytical and spectroscopic techniques. Additionally, electrochemical techniques have also been used for compound 1 a . X‐ray analysis revealed substantial differences between both compounds: whereas a six‐coordinated MnII compound with water molecules bridging two MnII centers has been observed for 1 a , a square pyramidal geometry around each MnII ion with terminal water molecules coordinated to each MnII center has been found for 1 b . The observed differences have been attributed to the existence of different substituents, ?CH3 or ?H, on one of the carbon atoms of the carboranylcarboxylate ligand. The reaction of 1 a and 1 b with coordinating solvents, such as ethers or Lewis bases, leads to the formation of new compounds with low (mononuclear 4 a , 4 b ; dinuclear 3 a , 3 b ; and trinuclear 2 a ) or high nuclearity (hybrid polymer, 5 a ), due to breakage of the corresponding polymer. X‐ray analysis shows that the structural core present in the polymeric materials is not maintained in the resulting compounds, with the exception of trinuclear compound 2 a . The magnetic properties of the compounds studied show weak antiferromagnetic coupling. 相似文献
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47.
Ermitas Alcalde Maria Gisbert Carmen Alvarez-Rúa Santiago García-Granda 《Tetrahedron》1996,52(48):163-15196
The first X-ray crystallographic diffraction of an example of the title heterophanes built up from heterocyclic betaine subunits is reported and its quadrupolar character is confirmed. The crystal packing of 2·4H2O is mainly governed by hydrogen-bonding networks, strong intermolecular interactions with water together with weak interactions, either intramolecular or with water. 相似文献
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50.
Alcalde E Mesquida N Vilaseca M 《Rapid communications in mass spectrometry : RCM》2000,14(16):1443-1447
Electrospray ionization mass spectral analysis of simple dicationic imidazolium prototypes (M.2X) is reported and direct observation was obtained for proton-mediated ion-molecule reactions in the gas phase. The comparative ESI-MS study with heterophanes 1a.2Cl and 3.2Br, the open chain system 5.2Br, and their regiospecific deuterated counterparts 2a.2Cl, 4.2Br and 6.2Br showed that the nature of the frameworks containing two imidazolium subunits modulates their electrospray ionization, changing the stability of the common characteristic peaks: the carbene specie [M - H](+) or [M - D](+) as well as [M](2+) and [M. X](+).Copyright 2000 John Wiley & Sons, Ltd. 相似文献