Abstract
Squaraine dyes are known for their particular optical properties. They exhibit intense photochemically stable fluorescence in usually (near) infra red region that can be quenched by intermolecular interactions. Moreover, even the centrosymmetric dyes feature non-zero second harmonic generation upon aggregation. Therefore, the detailed knowledge of the squaraine dye interaction nature both in homogenic aggregates and with other species present in the environment can be of importance for the design of new materials of desired properties. In the present study, interaction in squaraine dimers is investigated with quantum chemistry tools. Four structures: two stacked and two hydrogen-bonded are analyzed in terms of supermolecular approach and symmetry-adapted perturbation theory. MP2C/aug-cc-pVTZ supermolecular calculations confirm the particular stability of the stacked dimers and the favoured dispersion attraction for the long-displaced system.
Highlights
Even such a delicate change of the computational methodology as the modification of the dispersion correction can lead to the localization of the different minima than those found in other approaches
One can notice that in contrast to (SCS-)SAPT0, for DFT-SAPT the dispersion energy component presented in Table 3 is almost identical for lS and sS squaraine dimer and close to each other for both Hb systems. This overestimation of the stability of the long-displaced stacked dimer and lHB-B3LYP one leads to the disturbed total interaction energy ordering for DFT-SAPT (Fig. 3) with respect to the stability estimated with MP2C or SAPT0 approaches
Dimerization of 2,4-bis[4-(dimethyloamine)fenyl]cyclobutane-1,3-diole molecules is investigated with quantum chemistry approaches
Summary
The general analysis of the relative errors of the interaction energy with respect to the recommended SCSSAPT0/aug-cc-pVDZ data reveals that among the spin-component corrected approaches the augmentation of the basis set with the diffuse functions leads to the differences smaller than 10%.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call