Mifflin Amanda L, Musorrafiti Michael J, Konek Christopher T, Geiger Franz M
Department of Chemistry and the Institute for Environmental Catalysis, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
J Phys Chem B. 2005 Dec 29;109(51):24386-90. doi: 10.1021/jp055174n.
Surface second harmonic generation (SHG) phase measurements are carried out on methyl ester-functionalized fused quartz/water interfaces in the presence and absence of Cr(VI). The experiments are performed at pH 7, room temperature, and a chromate concentration of 10(-4) M, which corresponds to monolayer Cr(VI) coverage. The liquid/solid interface is probed from the fused quartz side by directing the probe light field at 580 nm onto the interface together with an SHG reference signal at 290 nm that is collinear with the fundamental. The phase difference of the SHG signals generated at the interface in the presence and absence of Cr(VI) is 85 degrees, which is consistent with SHG resonance enhancement observed for the surface-bound Cr(VI) near 290 nm. The optical arrangement discussed here does not require vacuum technology or optics that compensate for the dispersion of the fundamental and the second harmonic E-fields in the two condensed-phase media. This approach is general and can be applied for analyzing thermodynamic and kinetic data derived from SHG measurements of physical and chemical processes occurring at any buried interface.
在有和没有Cr(VI)存在的情况下，对甲酯功能化的熔融石英/水界面进行表面二次谐波产生（SHG）相位测量。实验在pH值为7、室温以及铬酸盐浓度为10⁻⁴ M的条件下进行，该浓度对应单层Cr(VI)覆盖。通过将580 nm的探测光场与290 nm的SHG参考信号一起导向界面，从熔融石英一侧探测液/固界面，SHG参考信号与基频光共线。在有和没有Cr(VI)存在的情况下，界面处产生的SHG信号的相位差为85度，这与在290 nm附近观察到的表面结合的Cr(VI)的SHG共振增强一致。这里讨论的光学装置不需要真空技术或用于补偿两种凝聚相介质中基频光和二次谐波电场色散的光学器件。这种方法具有通用性，可用于分析从任何埋藏界面发生的物理和化学过程的SHG测量中获得的热力学和动力学数据。
