To examine the strengths and limitations of the time-dependent density functional theory in calculating the absorption wavelengths of dye, 130, non-radical, radical and biradical coloured organic compounds, including perylenimide, porphyrin, azobenzene, quinone, croconaine, squaraine and push–pull-type colorants, were randomly selected. The first intense electronic transitions were satisfactori...

We study the interplay between a Kekul\'e patterned distortion in monolayer graphene and monochromatic laser irradiation, focusing long wavelength approximation of its Landau level structure. Exploiting symmetries system, we calculate static regime an exact analytical solution for energy spectrum eigenstates, which turn allows us to find close expressions polarizations valley pseudospin degrees...

In graphene, a Kekul\'e-Y bond texture modifies the electronic band structure generating two concentric Dirac cones with different Fermi velocities lying in {\Gamma}-point reciprocal space. The energy dispersion results group for each isospin component at given energy. This spectrum combined negative refraction index p-n junctions, allows emergence of an analog optical birefringence graphene. W...

The low-energy excitations of graphene are relativistic massless Dirac fermions with opposite chiralities at valleys K and K'. Breaking the chiral symmetry could lead to gap opening in analogy dynamical mass generation particle physics. Here we report direct experimental evidences breaking (CSB) from both microscopic spectroscopic measurements a Li-intercalated graphene. CSB is evidenced by poi...

Magic-sized clusters, as the intermediate state between molecules and nanoparticles, exhibit critical transitions of structures and material properties. We report two unique structures of gold clusters solved by x-ray crystallography, including Au40 and Au52 protected by thiolates. The Au40 and Au52 clusters exhibit a high level of complexity, with the gold atoms in the cluster first segregated...