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51.
Rodriguez KR Tian H Heer JM Teeters-Kennedy S Coe JV 《The Journal of chemical physics》2007,126(15):151101
The interaction of an infrared surface plasmon and an excited molecular vibration was investigated by using a square array of subwavelength holes in a Ni film which supports propagating, surface-plasmon-mediated, transmission resonances. The largest transmission resonance [the (1,0)(-)] was tuned through the rocking vibration of the hexadecane molecule (at 721 cm(-1)) in a hexadecane film on the mesh by varying the thickness of the film. The interaction of the rocking vibration and surface plasmon is characterized spectroscopically by an increase in the intensity of the vibrational band by more than a factor of 2, variation of the vibrational line shape relative to the spectrum on a nonmetallic surface, and shifts in vibrational peak position by as much as 3.0 cm(-1). Relationships are developed between the transmission resonance position and the thickness and dielectric properties of the coating. 相似文献
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A series of RuII or FeII trischelate complex salts containing N-methyl/aryl-2,2':4,4' ':4',4' '-quaterpyridinium ligands that has previously been subjected to quadratic nonlinear optical studies (Coe, B. J. et al. J. Am. Chem. Soc. 2005, 127, 13399) has now been investigated for two-photon absorbing behavior. Z-scan measurements using a 750 nm laser afford reasonably large two-photon absorption (2PA) cross-sections sigma2 of ca. 62-180 GM for the RuII complexes, but only very weak 2PA is observed for the FeII compounds. The excited-state and 2PA properties of the representative chromophore [RuII(Me2Qpy2+)3]8+ (Me2Qpy2+=N' ',N' '-dimethyl-2,2':4,4' ':4',4' '-quaterpyridinium) have also been investigated by using semiempirical intermediate neglect of differential overlap/multireference-determinant single and double configuration interaction computations with the optimized geometry obtained via density functional theory. The calculated sigma2 value of ca. 624 GM at 1.70 eV for this metal-to-ligand charge-transfer chromophore is about 10 times larger than that obtained from the Z-scan studies. 相似文献
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The Ca:P ratio in a certified standard of hydroxyapatite was determined by X‐ray spectrometry (XRS), with the X‐rays excited by both electrons and ions using energy dispersive spectroscopy on the scanning electron microscope (SEM‐EDS) and particle‐induced X‐ray emission (PIXE). The certified value of Ca:P was accurately verified by 3 MeV 4He+ Rutherford Backscattering Spectrometry (RBS). We show that the demonstrably rough surface of this sample does not cause perturbation of the Ca:P ratio within the uncertainties of each of the XRS measurements. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Benjamin J. Coe Stephan Houbrechts Inge Asselberghs Andr Persoons 《Angewandte Chemie (International ed. in English)》1999,38(3):366-369
Low‐energy metal‐to‐ligand charge‐transfer (MLCT) excitations are associated with the very large molecular nonlinear optical (NLO) coefficients, β, of the complexes [RuII(NH3)5(N‐R‐4,4′‐bipyridinium)]3+ (R=methyl, phenyl, or 4‐acetylphenyl). Chemical oxidation to the RuIII forms causes bleaching of the MLCT absorptions and marked attenuation of the NLO responses. Both effects are completely reversed upon re‐reduction, and the extent of the β switching is about 10‐ to 20‐fold. 相似文献
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An experimental modification has improved dehydrofluorinations of undeca- deca- and nona- fluoroeyclohexanes, and enhanced the proportions of dienes and aromatics formed. 相似文献
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The use of NbCl5, MoCl5, TaCl5 and WCl6 as reagents to effect the replacement by chlorine of the hydroxyl group in cyclohexanol has been investigated. Selective and almost complete conversion of cyclohexanol to cyclohexyl chloride was achieved using WCl6 or TaCl5. The chlorination reactions of cyclohexylmethanol, tetrahydrofurfuryl alcohol, tetrahydropyran-2-methanol and tetrahydro-4H-pyran-4-ol were also investigated. 相似文献