Oklejas Vanessa, Sjostrom Chris, Harris Joel M
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112-0850, USA.
J Am Chem Soc. 2002 Mar 20;124(11):2408-9. doi: 10.1021/ja017656s.
The vibrational Stark effect is observed in the surface-enhanced Raman scattering spectra of self-assembled monolayers functionalized with pendant nitrile groups. Stark tuning of the nitrile-stretching frequency serves as a localized probe of the electric field in the diffuse double layer of a SAM-modified electrochemical interface. Stark-tuning rates at low ionic strength correspond to reasonable values of the local electric (E) field in the double layer. The nitrile-stretching frequency converges on its isotropic value at applied potentials approaching the PZC, which indicates that Stark-tuning of the frequency is a direct probe of the E field at the interface. Loss of the local electric field at high ionic strengths shows that the probe responds to changes in the Debye length of the double layer. The results demonstrate the applicability of this electric-field probe for characterizing the diffuse double-layer region.
在带有侧链腈基官能团的自组装单分子层的表面增强拉曼散射光谱中观察到了振动斯塔克效应。腈基伸缩频率的斯塔克调谐作为SAM修饰的电化学界面扩散双电层中电场的局部探针。低离子强度下的斯塔克调谐速率对应于双电层中局部电场（E）的合理值。在接近零电荷电位（PZC）的外加电位下，腈基伸缩频率收敛于其各向同性值，这表明频率的斯塔克调谐是界面处电场的直接探针。高离子强度下局部电场的丧失表明该探针响应双电层德拜长度的变化。结果证明了这种电场探针在表征扩散双电层区域方面的适用性。
