Ferroelectrical spin wave resonance

New phenomenon is experimentally identified: ferroelectrical spin wave resonance (FE SWR), which consist in characteristic splitting of vibration (electronic-vibration) levels in optical spectra of interacting localized centers. Spectral positions of ESWR lines are determined in linear approach by quadratic dispersion law. It has been found that the values of resonance mode amplitudes are inversely proportional to mode numbers (by low excitation level). The prediction that Raman-ESWR and IR-ESWR are characterized by splitting constants with different values has been confirmed. Their ratio is approximately equal two (by the frequencies of zero modes reduced to the same value). It is independent argument for FE SWR identification.Comment: in russia

Dynamics of molecular self-ordering in tetraphenyl porphyrin monolayers on metallic substrates

A molecular model system of tetraphenyl porphyrins (TPP) adsorbed on metallic substrates is systematically investigated within a joint scanning tunnelling microscopy/molecular modelling approach. The molecular conformation of TPP molecules, their adsorption on a gold surface and the growth of highly ordered TPP islands are modelled with a combination of density functional theory and dynamic force field methods. The results indicate a subtle interplay between different contributions. The molecule-substrate interaction causes a bending of the porphyrin core which also determines the relative orientations of phenyl legs attached to the core. A major consequence of this is a characteristic (and energetically most favourable) arrangement of molecules within self-assembled molecular clusters; the phenyl legs of adjacent molecules are not aligned parallel to each other (often denoted as pi-pi stacking) but perpendicularly in a T-shaped arrangement. The results of the simulations are fully consistent with the scanning tunnelling microscopy observations, in terms of the symmetries of individual molecules, orientation and relative alignment of molecules in the self-assembled clusters