Resonance hyper-Raman excitation profiles and two-photon states of a donor-acceptor substituted polyene.
Resonance hyper-Raman excitation profiles and two-photon states of a donor-acceptor substituted polyene.
复制标题
供体-受体取代多烯的共振超拉曼激发曲线和双光子态。
DOI：
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发表时间：
2005
影响因子：
2.9
通讯作者：
A. Kelley
中科院分区：
文献类型：
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作者：
L. Shoute;M. Blanchard‐Desce;A. Kelley
共振拉曼和共振超拉曼光谱和激发轮廓已被测量的“推挽”的供体-受体取代的共轭多烯轴承久洛尼定供体基团和硝基苯基受体基团，在丙酮中的激发波长从485至356 nm（双光子波长的非线性光谱）。这些波长跨越了强可见光到近紫外线的线性吸收光谱，这似乎涉及至少三种不同的电子跃迁。不同振动带的相对强度在整个激发光谱中变化很大，超拉曼光谱显示出比线性拉曼更大的变化。一个先前推导出的共振超拉曼强度的理论进行修改，包括从纯粹的振动水平的基态电子作为中间状态的双光子吸收过程中的贡献。发现这些贡献对超瑞利强度和轮廓只有轻微的影响，但它们显着影响一些超拉曼轮廓。的吸收光谱和拉曼，超瑞利和超拉曼激发配置文件的假设下，三个激发电子态有助于在该区域的单光子和双光子吸收定量模拟。中心在400 nm附近的跃迁主要集中在硝基苯基上，而475和355 nm附近的跃迁则更加离域。
Resonance Raman and resonance hyper-Raman spectra and excitation profiles have been measured for a "push-pull" donor-acceptor substituted conjugated polyene bearing a julolidine donor group and a nitrophenyl acceptor group, in acetone at excitation wavelengths from 485 to 356 nm (two-photon wavelengths for the nonlinear spectra). These wavelengths span the strong visible to near-UV linear absorption spectrum, which appears to involve at least three different electronic transitions. The relative intensities of different vibrational bands vary considerably across the excitation spectrum, with the hyper-Raman spectra showing greater variation than the linear Raman. A previously derived theory of resonance hyper-Raman intensities is modified to include contributions from purely vibrational levels of the ground electronic state as intermediate states in the two-photon absorption process. These contributions are found to have only a slight effect on the hyper-Rayleigh intensities and profiles, but they significantly influence some of the hyper-Raman profiles. The absorption spectrum and the Raman, hyper-Rayleigh, and hyper-Raman excitation profiles are quantitatively simulated under the assumption that three excited electronic states contribute to the one- and two-photon absorption in this region. The transition centered near 400 nm is largely localized on the nitrophenyl group, while the transitions near 475 and 355 nm are more delocalized.