EXCITED-STATE STRUCTURE AND ELECTRONIC DEPHASING TIME OF NILE BLUE FROM ABSOLUTE RESONANCE RAMAN INTENSITIES
EXCITED-STATE STRUCTURE AND ELECTRONIC DEPHASING TIME OF NILE BLUE FROM ABSOLUTE RESONANCE RAMAN INTENSITIES
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DOI：
10.1063/1.462355
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发表时间：
1992-06-01
影响因子：
4.4
通讯作者：
MATHIES, RA
中科院分区：
文献类型：
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作者：
LAWLESS, MK;MATHIES, RA
用514、531和568 nm激发，测量了尼罗蓝690高氯酸盐在乙二醇中的绝对共振拉曼截面。 这些值和吸收光谱建模使用随时间变化的波包形式主义。 激发态平衡几何结构的变化进行了定量的40共振拉曼活性模式，其中七个（590，1141，1351，1429，1492，1544，和1640 cm-1）进行70%的总共振拉曼强度。 这表明，除了突出的590和1640 cm-1模式，大量的振动自由度是弗兰克-康登耦合到电子跃迁。 暴露后的明确的振动级数，剩余的吸收线宽被分离成其均匀的[350 cm-1的半峰半宽（HWHM）]和不均匀的（313 cm-1 HWHM）通过分析的绝对拉曼截面的组件。 本研究得出的电子失相时间值（25 fs）与之前发表的结果相当。 这些数据应该是有价值的多模建模飞秒实验尼罗河蓝。
Absolute resonance Raman cross sections are measured for Nile blue 690 perchlorate dissolved in ethylene glycol with excitation at 514, 531, and 568 nm. These values and the absorption spectrum are modeled using a time-dependent wave packet formalism. The excited-state equilibrium geometry changes are quantitated for 40 resonance Raman active modes, seven of which (590, 1141, 1351, 1429, 1492, 1544, and 1640 cm-1) carry 70% of the total resonance Raman intensity. This demonstrates that in addition to the prominent 590 and 1640 cm-1 modes, a large number of vibrational degrees of freedom are Franck-Condon coupled to the electronic transition. After exposure of the explicit vibrational progressions, the residual absorption linewidth is separated into its homogeneous [350 cm-1 half-width at half-maximum (HWHM)] and inhomogeneous (313 cm-1 HWHM) components through an analysis of the absolute Raman cross sections. The value of the electronic dephasing time derived from this study (25 fs) compares well to previously published results. These data should be valuable in multimode modeling of femtosecond experiments on Nile blue.