Orbital current

Current Patents Data-Star, ORBIT Current Dmgs Ltd. international, pharmaceutical bibhographic data English language abstract focused on pharmaceutical utihty... 

The general relativistic Hohenberg-Kohn-Sham formalism, outlined above, contains the spin degrees of freedom in a complete form. Consequently, the spin and kinetic motion effects are not separable. Indeed, they are contained in the external potential term as one can see if such term is written using the orbital current... 

In order to describe the coupling of time-dependent magnetic fields to the electronic orbital currents, the kinetic energy f has to be replaced by... 

Ab initio calculations using the IGLO method were able to answer the question whether there is an extra contribution from real circulating aromatic currents.Since the IGLO works with localized electrons, it must fail to include this effect since only orbital currents in localized orbitals are properly described. No special ring current effect in... 

Neglect, for the sake of argument, the coupling of V to the orbital current,... 

Figure 5.2 Orbital current density jp for BCC-Fe in the (001) plane (left). The right part gives the corresponding radial component scaled by a factor of around 350 with respect to the left part of the figure. For display jp has been weighted with r2.

A further consequence of the presence of the spin-orbit coupling for a spin-polarized solid is that its orbital angular momentum is quenched no more. This corresponds to the occurrence of a finite paramagnetic orbital current density jp, which can be obtained from the expression... 

With the spin-orbit-induced orbital current density in magnetic solids there is obviously a finite orbital angular momentum density associated. The corresponding orbital magnetic moment /xorb can be obtained from the expression (Ebert et al. 1988a) ... 

The basic CDFT Hamiltonian in Equation (5.6) does not rule out the existence of a finite orbital magnetic moment in the nonrelativistic limit. With the help of model calculations, it could be demonstrated that this is not the case for bulk Fe, Co and Ni (Ebert et al. 1997a). Starting an SCF calculation with a finite spin-orbit-induced orbital current density and switching off the spin-orbit coupling during the SCF-cycle the orbital magnetic moment vanished (see also next section). 

A difficulty with this local approach to dynamical correlation is that, in Moller-Plesset theory, for example, the zero-order Fock operator is no longer diagonal in the space of the Slater determinants, making the application of such theories slightly more complicated than theories based on canonical orbitals. Currently, the development of local correlation methods is an active area of research [57-63]. The diatomics-inmolecules (DIM) method and the triatomics-in-molecules (TRIM) method, for instance, recover typically 95% and 99.7%, respectively, of the full MP2 correlation energy [63]. By means of a linear scaling local variant of the CCSDT method,... 

Bgxt —> 0 is easily taken. On the other hand, if Bgj i 0, the Hamiltonian (90) can be viewed as an approximation, neglecting the coupling between Bg t and the orbital current. 

The relativistic generalisation of the Hohenberg-Kohn theorem states that the external four-potential is - except for a gauge transformation - determined by the four-current of the system. The first component e7° is the charge density while the spatial components, J are associated both with orbital currents and the spin density. In the non-relativistic limit, the coupling of electron spin to an external magnetic field is automatically retrieved. 

Ba), via Zeeman-perturbed Ba NQR spectroscopy. No evidence was found for orbital currents (additional local fields) at the Ba site. Any static or dynamic fields must be less than 0.07 and 0.7 mT respectively (the detection limits of the method). 

Jonsson, K.I., Rabbow, E., Schill, R.O., Briimmer, F. (2008). Tardigrades survive exposure to space in low Earth orbit. Current Biology 18, R729-R731. 

Being the orbital area A = nr that associates with the orbital current, the corresponding magnetic moment can be written as their product ... 

When placed in a magnetic field Bo, the cloud of electrons about each nucleus produces orbital currents which are accompanied by small local magnetic fields proportional to Bq but in the opposite direction (diamagnetic), thereby effectively shielding the nucleus from Bq. A slightly higher value of Bq is needed to achieve resonance, because the actual local magnetic field Bioc experienced by a nucleus is expressed as... 

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