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Spin-orbit Interaction (spin-orbit + interaction)
Selected AbstractsRelativistic and electron-correlation effects on magnetizabilities investigated by the Douglas-Kroll-Hess method and the second-order Møller-Plesset perturbation theoryJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2009Terutaka Yoshizawa Abstract Isotropic and anisotropic magnetizabilities for noble gas atoms and a series of singlet and triplet molecules were calculated using the second-order Douglas-Kroll-Hess (DKH2) Hamiltonian containing the vector potential A and in part using second-order generalized unrestricted Møller-Plesset (GUMP2) theory. The DKH2 Hamiltonian was resolved into three parts (spin-free terms, spin-dependent terms, and magnetic perturbation terms), and the magnetizabilities were decomposed into diamagnetic and paramagnetic terms to investigate the relativistic and electron-correlation effects in detail. For Ne, Kr, and Xe, the calculated magnetizabilities approached the experimental values, once relativistic and electron-correlation effects were included. For the IF molecule, the magnetizability was strongly affected by the spin-orbit interaction, and the total relativistic contribution amounted to 22%. For group 17, 16, 15, and 14 hydrides, the calculated relativistic effects were small (less than 3%), and trends were observed in relativistic and electron-correlation effects across groups and periods. The magnetizability anisotropies of triplet molecules were generally larger than those of similar singlet molecules. The so-called relativistic-correlation interference for the magnetizabilities computed using the relativistic GUMP2 method can be neglected for the molecules evaluated, with exception of triplet SbH. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009 [source] Spin-Hall effect and spin coherent waves in semiconductors with Rashba spin-orbit interactionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008P. Kleinert Abstract Based on rigorous quantum-kinetic equations for the spin-density matrix, spin-charge coupled drift-diffusion equations are derived for a strongly confined twodimensional hole gas. An electric field leads to a coupling between the spin and charge degrees of freedom. For weak spin-orbit interaction, this coupling gives rise to the intrinsic spin-Hall effect that occurs in the diffusive regime. There exists a threshold value of the spin-orbit coupling constant that separates spin diffusion from ballistic spin transport. In the latter regime, undamped spin-coherent oscillations are observed. Their relationship to the zitterbewegung is discussed. The analytic results are compared with an exact microscopic approach valid in the ballistic regime. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Light scattering in an electron-hole double quantum well in the presence of spin-orbit interactionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007C. H. Yang Abstract In this work, we study theoretically the lineshape and intensity of light scattering in an electron-hole double quantum well structure in the presence of spin-orbit interaction (SOI). Using the random phase approximation and Green function approach, the dispersion and the excitation spectra in this structure have been calculated. It is shown that scattering intensity can be tuned by the spin-orbit (SO) couple via the applied electrical field. The peaks shift as the polarization of electron or hole increases. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spin densities in parabolic quantum wires with Rashba spin-orbit interactionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2006Sigurdur I. Erlingsson Abstract Using canonical transformations we diagonalize approximately the Hamiltonian of a gaussian wire with Rashba spin-orbit interaction. This proceedure allows us to obtain the energy dispersion relations and the wavefunctions with good accuracy, even in systems with relatively strong Rashba coupling. With these eigenstates one can calculate the non-equilibrium spin densities induced by applying bias voltages across the sample. We focus on the z -component of the spin density, which is related to the spin Hall effect. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Observation of 4f electron transfer from Ce to B6 in the Kondo crystal CeB6 and its mechanism by multi-temperature X-ray diffractionACTA CRYSTALLOGRAPHICA SECTION B, Issue 3-2 2002Kiyoaki Tanaka Electron density distributions (EDD) in CeB6 were measured by X-ray diffraction at 100, 165, 230 and 298,K. Analysis with a weak-field model, in which the spin-orbit interaction dominates the energy splitting of the 4f levels, revealed that more 4f electrons were donated from Ce to B6 at the lower temperature. Donated electrons localize around the B,B bonds connecting B6 octahedra. The localized electrons and an expansion of the outermost 5p orbitals change the effective atomic potentials and enhance the anharmonic vibration (AHV) of constituent atoms at lower temperature. Enhanced AHV increases the entropy and makes the electron donation inevitable. Changes in crystal structure, EDD, electron configuration and AHV are found to be closely correlated with one another and the mechanism of the electron transfer in the Kondo crystal CeB6 in the studied temperature range was elucidated. This is, to the authors' knowledge, the first multi-temperature measurement of EDD that elucidates a mechanism of change from the temperature dependence of the EDD. Parameters change consistently at all the temperatures except 298,K, at which the excited states ,7 of the Ce 4f states have significant electron population. The thermal excitation to ,7 levels expands the B6 octahedra, since ,7 has main lobes along ,111, or from Ce to the centre of B6 octahedra. The energy gap between the ground state ,8 and ,7 was calculated to be 470,K from the ratio of electron populations of both states. The present experiment opens the door to accurate X-ray EDD analyses of rare earth complexes. [source] Muon Implantation of Metallocenes: FerroceneCHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2007Upali Abstract Muon Spin Relaxation and Avoided Level Crossing (ALC) measurements of ferrocene are reported. The main features observed are five high field resonances in the ALC spectrum at about 3.26, 2.44, 2.04, 1.19 and 1.17,T, for the low-temperature phase at 18,K. The high-temperature phase at 295,K shows that only the last feature shifted down to about 0.49,T and a muon spin relaxation peak at about 0.106,T which approaches zero field when reaching the phase transition temperature of 164,K. A model involving three muoniated radicals, two with muonium addition to the cyclopentadienyl ring and the other to the metal atom, is postulated to rationalise these observations. A theoretical treatment involving spin-orbit coupling is found to be required to understand the Fe,Mu adduct, where an interesting interplay between the ferrocene ring dynamics and the spin-orbit coupling of the unpaired electron is shown to be important. The limiting temperature above which the full effect of spin-orbit interaction is observable in the ,SR spectra of ferrocene was estimated to be 584,K. Correlation time for the ring rotation dynamics of the Fe,Mu radical at this temperature is 3.2,ps. Estimated electron g values and the changes in zero-field splittings for this temperature range are also reported. [source] Spin-Orbit Ab Initio Investigation of the Ultraviolet Photolysis of DiiodomethaneCHEMPHYSCHEM, Issue 6 2007Ya-Jun Liu Dr. Abstract The UV photodissociation (<5 eV) of diiodomethane (CH2I2) is investigated by spin-orbit ab initio calculations. The experimentally observed photodissociation channels in the gas and condensed phases are clearly assigned by multi-state second-order multiconfigurational perturbation theory in conjunction with spin-orbit interaction through complete active space-state interaction potential energy curves. The calculated results indicate that the fast dissociations of the first two singlet states of CH2I2 and CH2II lead to geminate-radical products, CH2I,.+I(2P3/2) or CH2I,.+ I*(2P1/2). The recombination process from CH2II to CH2I2 is explained by an isomerization process and a secondary photodissociation reaction of CH2II. Finally, the study reveals that spin-orbits effects are significant in the quantitative analysis of the electronic spectrum of the CH2II species. [source] | ||||||||||