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Second-order nonlinear optical properties of [formula omitted]-shaped pyrazine derivatives.
- Source :
-
Dyes & Pigments . Jan2021, Vol. 184, pN.PAG-N.PAG. 1p. - Publication Year :
- 2021
-
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. • Λ -shaped pyrazine derivatives deliver strong second-order NLO responses. • They result from the contribution of low-lying perpendicular electronic transitions. • The first hyperpolarizabilities are not Kleinman-symmetric. • These second-order NLO responses have a dominant dipolar character. • Their amplitudes depend on the nature of the π-conjugated linkers. [ABSTRACT FROM AUTHOR]
- Subjects :
- *OPTICAL properties
*DENSITY functional theory
*NONLINEAR optics
Subjects
Details
- Language :
- English
- ISSN :
- 01437208
- Volume :
- 184
- Database :
- Academic Search Index
- Journal :
- Dyes & Pigments
- Publication Type :
- Academic Journal
- Accession number :
- 146496539
- Full Text :
- https://doi.org/10.1016/j.dyepig.2020.108850