Landau developed the idea of quasiparticle excitations in the context of interacting Fermi systems. His theory is known as Fermi liquid theory. He introduced the idea phenomenologically, and later Abrikosov and Kalatnikov gave a formal derivation using diagrammatic perturbation theory to all orders. Landau suggested describing the excited states of the interacting system as in one-to-one corres...

The intrinsic spin–orbit interactions in bilayer graphene and in graphite are studied, using a tight binding model and an intra-atomic E LE S coupling. The spin–orbit interactions in bilayer graphene and graphite are larger, by about one order of magnitude, than the interactions in single-layer graphene, due to the mixing of π and σ bands by interlayer hopping. Their values are in the range 0.1...

Pyrylium salts are a very important class of organic molecules containing a trivalent oxygen atom in a six-membered aromatic ring. In this manuscript, we report a theoretical study of pyrylium salts and their thio-, seleno- and telluro- analogues by means of DFT calculations. For this purpose, unsubstituted 2,4,6-trimethyl and 2,4,6-triphenyl cations and anions with different morphologies were ...

In this manuscript, we combined a search in the Cambridge Structural Database (CSD) and ab initio calculations (RI-MP2/def2-TZVPD level of theory) to analyze the ability of trisulphide and triselenide moieties to establish chalcogen 'like-like' interactions. A preliminary CSD inspection revealed two predominant structural patterns, depending on the anti or syn conformation adopted by the substi...

We have synthesized a series of molecules wherein very close C-F---H-C σ-bond interactions, which we have termed "jousting", can be perturbed through both red- and blue-shifted hydrogen bonding effects. These interactions were induced by the placement of various functional groups geminal to the H-C bond. "Jousting" interactions appear to be an admixture of F---H hydrogen bonding and C-H bond co...

The phase behavior of a kind of pseudogemini surfactant in aqueous solutions, formed by the mixture of sodium dodecyl benzene sulfonate (SDBS) and butane-1,4-bis (methylimidazolium bromide) ([mim-C4-mim]Br2) or butane-1,4-bis(methylpyrrolidinium bromide) ([mpy-C4-mpy]Br2) in a molar ratio of 2 : 1, is reported in the present work. When [mim-C4-mim]Br2 or [mpy-C4-mpy]Br2 is mixed with SDBS in aq...