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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 7590-7599 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Frequently it is useful to compare experimental values of the hyperpolarizabilities β and γ with calculated values. It is also often helpful to compare experimental values of β obtained from dc-electric field induced second harmonic generation (dc-SHG) experiments, e.g., with values obtained using the solvatochromism method. In order to do this the hyperpolarizabilities must be defined using consistent conventions. In this paper, four commonly used conventions are discussed and simple factors for converting between them presented. In addition, the sum-over-states expression for the calculation of β and γ is described and its correct use in comparing with hyperpolarizabilities obtained using other experimental and theoretical techniques discussed. As an illustration of the consistent use of conventions, ab initio and semiempirical calculations on para-nitroaniline are compared with experimental dc-SHG values. This comparison highlights the difference between theoretical values of the hyperpolarizability with the molecule in a gas phase environment and experimental values obtained in polar solvents−a difference that has in the past been obscured by inconsistent choice of conventions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 3918-3929 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Hyper-Rayleigh light scattering measurements at incident wavelengths of 1064 and 1319 nm are reported for several organic nonlinear optical chromophores in solution with approximately 5%–10% uncertainty in the relative first hyperpolarizabilities. The measured chromophores include representatives from C1, Cs, C2V, and D3 molecular point groups and include both neutral and ionic compounds. The measurements were made with 2–5 cm−1 spectral resolution and include polarization analysis of the incident and scattered light. Polarization ratios were measured with 2%–3% uncertainty for each molecule, and relative magnitudes of the hyperpolarizability components were deduced. Two-photon induced fluorescence from several chromophores was observed to overlap with the scattered second harmonic light spectrum. The use of a scanning monochromator, however, generally allows the separation of these two sources of photons. The measured first hyperpolarizabilities are consistent with previous electric field induced second harmonic generation measurements of the same compounds, provided that the standard reference value for the nonlinear susceptibility of quartz is taken to be d11=0.30±0.02 pm/V at 1064 nm. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Chemical reviews 94 (1994), S. 3-29 
    ISSN: 1520-6890
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 849-856 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The first and second hyperpolarizabilities (β and γ) of eight molecules at a fundamental wavelength of 1064 were measured by gas-phase electric-field-induced second-harmonic generation (EFISH), gas-phase hyper-Rayleigh scattering (HRS), and liquid-phase HRS experiments. The EFISH measurements give accurate values of β and γ for these molecules in the gas phase, and the HRS measurements show that the effective β of these molecules in the liquid is enhanced over the gas-phase value by a factor which varies from (approximate)0.4 to 2.0, over and above the Lorentz local field factors. Combining all of the measurements provides an accurate, absolute determination of the effective β for HRS in the liquid phase. The results for CCl4, suitable as reference standards, are 〈βVV2〉1/2=18.6±0.7 au in the liquid phase and βxyz=20.7±1.6 au in the gas phase. Comparison of measurements between hydrogenated and deuterated molecules indicates that vibrational contributions to β are small. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 9938-9946 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: First hyperpolarizabilities β were obtained for CX4 molecules in gas and liquid phases from hyper-Rayleigh scattering measurements at λ=1064 nm. The gas-phase results for βxyz (atomic units) are 7.1±0.9 (CH4), 7.0±0.9 (CD4), 5.4±0.6 (CF4), and 11.0±0.9 (CCl4). Ab initio calculations of β are consistent with the experimental results for CF4 and CCl4, but not for CH4 and CD4. The effective liquid-phase β for CCl4 is 3× the gas phase value, but the liquid environment has little effect on β for the other molecules. Thermal-lens and absorption coefficients were also measured for ten liquids. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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