Rotating/laboratory frame-driven

A pulse scheme recovering the zero-quantum Hamiltonian was proposed by Baldus and Meier.142 It is weakly dependent on spectral parameters and a faithful measure of internuclear distances. This sequence is based on the former rotor-synchronized R/L-driven polarization transfer experiments.143,144 It uses the LG or FS-LG, which is used to decouple the high-7 spins, and combined MAS and RF irradiation of low-7 spins to decouple the hetero-nuclear dipolar interactions. With phase-inversion and amplitude attenuation in the rotating frame and refocusing pulses in the laboratory frame part of the pulse sequence, a zero-quantum average Hamiltonian can be obtained with optimum chemical-shift/offset independence. 

When the sample is placed in a gas-driven rotor and spun at the rate of a few kilohertz under 6 equal 54.7° (Figure IB and C), the anisotropic part is zero. In such an experiment, the so-called MAS, narrowing of the resonance lines is observed. However, it is only true when the spin rotation is larger than anisotropy A8 given in hertz. In cases when the rotor rotation (cor) < AS, the isotropic signal is flanked on both sides by rotational sidebands. In a strong applied field B0, the only measurable quantity of the shift tensor is the component oriented along z-axis in the laboratory frame ... 

Barth et al. performed a quantum simulation of laser-driven electron dynamics in Mg porphyrin, which is an aromatic molecule of symmetry [14]. The results of their simulation showed that n electrons of Mg porphyrin can be rotated around its aromatic ring by an ultrashort circularly polarized UV laser pulse propagating along its C4 axis. The rotation direction of n electrons is predetermined in a laboratory frame by that of the polarization plane of the circularly polarized laser pulse, that is, by photon angular momentum. 

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