Theoretical assessment of the influences of aromatic bridges on molecular second order nonlinear optical responses of Donor-Bridge-Acceptor types of molecular organic chromophores

Push-pull types Donor-Bridge-Acceptor (D-B-A) organic molecules have been reported as efficient functional materials for various technological applications. Often their interesting properties were reported to be directly linked to their nature of intramolecular charge transfers (ICT). Bridge that connects the D with A, plays the vital role in the ICT processes. A recent report of comparative experimental and computational nonlinear optical (NLO) study, shows many interesting behaviours exhibited by aromatic (diazine, thiophene and benzene rings) bridges. Many earlier studies also exist, where effects of one or more of aromatic bridges were investigated for NLO applications. But no systematic comparative study with well-known aromatic bridges at one place exist in literature. Inspired by those earlier works, this computational work reports the influences of a set of mono-aromatic ring bridges on NLO properties for a set of D-B-A types of organic molecules. This work can be expected to serve as a reference for many researchers working in the search of new and efficient functional materials.