@article{9f9c8e36691a4f8092eb8412b8452605,
title = "Second-order nonlinear optical properties of Λ-shaped pyrazine derivatives",
abstract = "The linear and nonlinear optical (NLO) properties of a series of Λ-shaped derivatives containing a 4,5-dicyanopyrazine acceptor unit, N,N-dimethylamino donor groups and systematically enlarged π-conjugated linkers are investigated by means of UV/Visible and Hyper-Rayleigh scattering spectroscopies. Density functional theory calculations are also carried out to rationalize the magnitude and symmetry of the NLO responses. The results demonstrate that these compounds possess two low-lying excited electronic states close to each other in energy, which are accessible through one-photon optical transitions respectively polarized perpendicular and parallel to the two-fold molecular axis. These two states contribute additively to the first hyperpolarizability, which exhibits a dominant dipolar character. We also show that the NLO responses significantly deviate from Kleinman's index permutation symmetry.",
keywords = "Density functional theory, First hyperpolarizability, Hyper-Rayleigh scattering, Kleinman symmetry, Nonlinear optics, Pyrazines",
author = "Fr{\'e}d{\'e}ric Castet and Adrien Gillet and Filip Bure{\v s} and Aur{\'e}lie Plaquet and Vincent Rodriguez and Beno{\^i}t Champagne",
note = "Funding Information: V.R. is grateful to F. Adamietz for experimental support and technical developments, as well as to the CNRS and the R{\'e}gion Nouvelle Aquitaine for funding support. F.B. is indebted to the Ministry of Education , Youth and Sports of the Czech Republic (LTAIN19101). This work was also supported by funds from the Belgian Government (IUAP No. P7/5 “Functional Supramolecular Systems”) and the Francqui Foundation. The calculations were performed on the computers of the Consortium des Equipements de Calcul Intensif , including those of the Technological Platform of High-Performance Computing, for which financial support from the FNRS-FRFC (Convention Nos. 2.4.617.07.F and 2.5020.11) is acknowledged, as well as on the M{\'e}socentre de Calcul Intensif Aquitain (MCIA) of the University of Bordeaux , financed by the Conseil R{\'e}gional d{\textquoteright}Aquitaine and the French Ministry of Research and Technology. Publisher Copyright: {\textcopyright} 2020 Elsevier Ltd Copyright: Copyright 2020 Elsevier B.V., All rights reserved.",
year = "2021",
month = jan,
day = "1",
doi = "10.1016/j.dyepig.2020.108850",
language = "English",
volume = "184",
journal = "Dyes and pigments",
issn = "0143-7208",
publisher = "Elsevier",
}