Dynamical exchange decoupling

Up to now, very few conclusions can be drawn concerning the dynamic correlations beyond the dynamical exchange decoupling. Even in the static limit, most recent studies make the approumation that G q,uj) is frequency-... 

The variational solution of the decoupled equation of motion (Eq. Ills) for the Wigner distribution function might serve as a starting point for further studies of exchange and correlation in the dielectric function. Its connection with several other approximations has been examined, showing that many of them are particular cases or additional approximations to this variational approach. The improvement upon the RPA from dynamical exchange effects, and the fact that all checked sum rules are satisfied, gives... 

Conformational motions have been studied." Other line shape experiments include 13c 481,482 P in freeze-dried liposomes,DNA," " cytochrome" and spectra of lipids. The complex dynamics in lipid bilayers was studied by H-2D exchange." Dynamic decoupling found its application" as well as multipulse experiments." SLF experiments like LG-CP," DIPSHIFT" " and determine the amplitudes of fast... 

As most of the electronic structure simulation methods, we start with the Born-Oppenheimer approximation to decouple the ionic and electronic degrees of freedom. The ions are treated classically, while the electrons are described by quantum mechanics. The electronic wavefunctions are solved in the instantaneous potential created by the ions, and are assumed to evolve adiabatically during the ionic dynamics, so as to remain on the Born-Oppenheimer surface. Beyond this, the most basic approximations of the method concern the treatment of exchange and correlation (XC) and the use of pseudopotentials. XC is treated within Kohn-Sham DFT [3]. Both the local (spin) density approximation (LDA/LSDA) [16] and the generalized gradients approximation (GGA) [17] are implemented. The pseudopotentials are standard norm-conserving [18, 19], treated in the fully non-local form proposed by Kleinman and Bylander [20]. 

As shown in [22] (similar results were independently obtained by others [52]), the simplest approach to the description of reaction probability is to assume full adiabatic decoupling and to treat the dynamics as scattering from the potentials generated by the adiabatic levels as p varies. Neglecting coupling in an adiabatic representation leads to the simplest description of the probabaility p for a symmetric exchange reaction, in terms of phaseshifts 6- rom even (+) and odd (-) potentials [53]... 

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