The second-order nonlinear optical (NLO) properties of [Ln(hfac)(3)(diglyme)] (hfac = hexafluoroacetylacetonate; diglyme = bis(2-methoxyethyl)ether; Ln = La, Ce, Pr, Sm, Eu, Gd, Er, Lu) complexes have been investigated by a combination of electric-field second harmonic generation (EFISH) and harmonic light scattering (HLS) techniques, providing evidence for the relevant role of f electrons in tuning the second-order NLO response dominated by the octupolar contribution. These lanthanide NLO chromophores allow a clean valuation of the influence of f electrons on the quadratic hyperpolarizability and on its dipolar and octupolar contributions. Molecular quadratic hyperpolarizability values measured by the EFISH method, beta(EFISH), initially increase rapidly with the number of f electrons, the value for the Gd complex being 11 times that of the La complex, whereas this increase is much lower for the last seven f electrons, the beta(EFISH) value of the Lu complex being only 1.2 times that of the Gd complex. The increase of beta(HLS), which is dominated by an octupolar contribution, is much lower along the Ln series. Remarkably, the good beta(HLS) values of these simple systems, well known for their luminescence properties, are reached at no cost of transparency.
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http://dx.doi.org/10.1021/ja101081q | DOI Listing |
Chem Sci
November 2024
College of Chemistry and Materials Science, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei Research Center of the Basic Discipline of Synthetic Chemistry, Key Laboratory of Chemical Biology of Hebei Province, Hebei University Baoding 071002 China
The exploration of crystal materials for optical manipulation by nonlinear optical (NLO) and anisotropic light-matter interaction is of paramount importance in modern science and technology. However, in such crystal materials, finding the right balance between second harmonic generation (SHG), birefringence, and the bandgap presents a significant challenge. In this contribution, we employ extended octupolar π-conjugated groups devoid of intrinsic dipole moments to construct melonate-based inorganic-organic hybrid crystals, thereby achieving simultaneous large optical nonlinearity and anisotropy.
View Article and Find Full Text PDFJ Chem Phys
December 2023
São Carlos Institute of Physics, University of São Paulo, São Carlos, 13560-970 São Paulo, Brazil.
The first-order molecular hyperpolarizability (β) dispersion was measured in seven chalcone-based molecules utilizing the tunable femtosecond hyper-Rayleigh scattering (tHRS) technique. Additionally, a theoretical model based on photophysical parameters was employed to better understand β dispersion. Due to the distinct substitution patterns of the aryl/heteroaryl rings within the chalcone structure, varying profiles of one- and two-photon absorption spectra and β dispersion were observed.
View Article and Find Full Text PDFChemphyschem
June 2023
Faculdade de Física, Universidade Federal do Sul e Sudeste do Pará, 68507-590, Marabá-PA, Brazil.
The solute polarization due to solvent is a an electrostatic quantum effect that impacts diverse molecular properties, including the nonlinear optical response of a material. An iterative procedure that allows updating the solute charge distribution in the presence of the solvent is combined with a sequential Monte Carlo/Quantum Mechanics methodology and Density Functional Theory methods to evaluate the nonlinear optical (NLO) response using the hyper Rayleigh scattering (HRS) of a series of chromones recently identified in Chamaecrista diphylla, an herbaceous plant abundant throughout the Americas and used in folk medicine. From this study, it is determined that from gas to solvent environment, the systems acquire low refractive index (n) and an improvement of the first hyperpolarizability (β ), signaling potential NLO uses.
View Article and Find Full Text PDFMolecules
February 2023
Department of Chemistry, Abbottabad Campus, COMSATS University Islamabad, Abbottabad 22060, KPK, Pakistan.
Carbon-based polynuclear clusters are designed and investigated for geometric, electronic, and nonlinear optical (NLO) properties at the CAM-B3LYP/6-311++G(d,p) level of theory. Significant binding energies per atom (ranging from -162.4 to -160.
View Article and Find Full Text PDFMolecules
April 2022
Theoretical Chemistry Laboratory, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, B-5000 Namur, Belgium.
This contribution employs quantum chemistry methods to describe the variations of the second nonlinear optical responses of molecular switches based on benzazolo-oxazolidine (BOX) units, connected by -linkers, along their successive opening/closing. Under the fully closed forms, all of them display negligible first hyperpolarizability () values. When one BOX is opened, which is sketched as →, a push-pull -conjugated segment is formed, having the potential to enhance and to set the depolarization ratio (DR) to its one-dimensional-like value (DR = 5).
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