Core-level binding energies of the component metals in bimetallic clusters of various compositions in the Ni-Cu, Au-Ag, Ni-Pd, and Cu-Pd systems have been measured as functions of coverage or cluster size, after having characterized the clusters with respect to sizes and compositions. The core-level binding energy shifts, relative to the bulk metals, at large coverages or cluster size, ∆E a , are found to be identical to those of bulk alloys. By substracting the ∆E a values from the observed binding energy shifts, ∆E, we obtain the shifts, ∆E c , due to cluster size. The ∆E c values in all the alloy systems increase with the decrease in cluster size. These results establish the additivity of the binding energy shifts due to alloying and cluster size effects in bimetallic clusters.

Merocyanine dyes that exhibit antithetic cyanine-like behaviour and giant first-order hyperpolarisability (β) values have been designed. These cyanine-type dyes open up an intriguing route towards molecular-based electro-optic materials as well as new second-harmonic generation dyes for imaging.

During past few decades, fuzzy decision is an important attention in the areas of science, engineering, economic system, business, etc. To solve day-to-day problem, researchers use fuzzy data in transportation problem for presenting the uncontrollable factors; and most of multi-objective transportation problems are solved using goal programming. However, when the problem contains interval-valued data, then the obtained solution was provided by goal programming may not satisfy by all decision-makers. In such condition, we consider a fixed-charge solid transportation problem in multi-objective environment where all the data are intuitionistic fuzzy numbers with membership and non-membership function. The intuitionistic fuzzy transportation problem transforms into interval-valued problem using $$(\alpha ,\beta )$$ ( α , β ) -cut, and thereafter, it reduces into a deterministic problem using accuracy function. Also the optimum value of alternative corresponds to the optimum value of accuracy function. A numerical example is included to illustrate the usefulness of our proposed model. Finally, conclusions and future works with the study are described.

We report the quadratic nonlinearity of one- and two-electron oxidation products of the first series of transition metal complexes of meso-tetraphenylporphyrin (TPP). Among many MTPP complexes, only CuTPP and ZnTPP show reversible oxidation/reduction cycles as seen from cyclic voltammetry experiments. While centrosymmetric neutral metalloporphyrins have zero first hyperpolarizability, beta, as expected, the cation radicals and dications of CuTPP and ZnTPP have very high beta values. The one- and two-electron oxidation of the MTPPs leads to symmetry-breaking of the metal-porphyrin core, resulting in a large beta value that is perhaps aided in part by contributions from the two-photon resonance enhancement. The calculated static first hyperpolarizabilities, beta0, which are evaluated in the framework of density functional theory by a coupled perturbed Hartree-Fock method, support the experimental trend. The switching of optical nonlinearity has been achieved between the neutral and the one-electron oxidation products but not between the one- and the two-electron oxidation products since dications that are electrochemically reversible are unstable due to the formation of stable isoporphyrins in the presence of nucleophiles such as halides.

We investigate the second-order nonlinear optical properties of a push-pull chromophore in different external and supramolecular environments, through a combined experimental and theoretical approach. In particular, we compare the first hyperpolarizability (beta) of a model dipolar and polarizable chromophore with that of a charged analogue and of a molecular dimer based on the chromophore itself. We find that the beta value of the model chromophore in solutions of low-polarity solvents is strongly affected by association effects, already at concentrations of 10 (-3) M. The presence of a positive charge in close proximity to the chromophore is found to lead to a 100% increase of the beta response of the model push-pull chromophore. This effect is of major importance for biological applications, in particular when chromophores are used as markers in charged anisotropic environments. Finally, excitonic effects, beyond the Frenkel exciton approximation, are discussed for the dimer and found to be more important the higher the order of nonlinearity is.