Correlating cluster size and NLO response of complexes aggregated with bifurcated metal bonds: a DFT study.

In the present work, the cooperativity effect on the NLO response of clusters aggregated with bifurcated metal bonds is reported by DFT calculations at the CAM-B3LYP/6-311++G(d,p) level. Linear clusters of (LiN(CHO)) and (NaN(CHO)) which are connected with bifurcated metal bonds have been selected as model systems. Stabilization energies, polarizability, first hyperpolarizability, energy gap of HOMO and LUMO, and charge transfer (CT) were obtained at the same level of optimization. In the studied clusters, first hyperpolarizability is increased by cluster size and its values were obtained in ranges of 606.1-1327.4 and 1239.4-2071.1 a.u. for (LiN(CHO)) and (NaN(CHO)) clusters, respectively. The many-body analysis was carried out to determine two-body and many-body contributions in total interaction-induced properties. TD-DFT calculations were performed to compute the crucial electronic transitions of the related clusters. UV-vis spectra exhibit red shift due to cooperativity effects. [ABSTRACT FROM AUTHOR]