測定有機分子的絕對拉曼散射截面在532 nm和 488 nm激發

Determination of Absolute Raman Cross Sections of Organic Molecules at 532 nm and 488 nm excitation

曾韋軒(Wei-Hsuan Tseng)

指導教授 ： 濵口宏夫

國立交通大學/理學院/分子科學研究所/碩士(2019年)

摘要

在自發拉曼散射的領域裡，拉曼散射截面作為重要的物理量可用於定量分子在特定振動躍遷的散射效率，在這個研究中，為了測定多種有機分子的絕對拉曼散射截面，以苯在992 cm-1振動峰的強度做為標準去定量其他有機分子的絕對拉曼散射截面，在儀器反應函數已經知道的前提下，在相同的環境下測量的樣品和標準品的振動峰的拉曼散射強度比值等同於其拉曼散射截面的比值，把樣品散射截面的比率乘以苯的992 cm-1振動峰在文獻中絕對拉曼散射截面的數值就能得到該樣品的絕對拉曼散射截面，本文中整理了28種有機分子在488 nm 和 532 nm 雷射激發的絕對拉曼散射截面以及討論前置共振效應對拉曼散射截面在不同波長激發下的影響，此外還包含苯丙胺酸在蛋白質裡的拉曼散射截面變化及探討環境靜電場對該分子的作用。

關鍵字

拉曼散射截面 ； 拉曼光譜學

並列摘要

In spontaneous Raman spectroscopy, a physical quantity known as Raman cross section plays an important role. It is an intrinsic measure of scattering efficiency of a specific vibrational transition of a molecule. In this study, determination of absolute Raman cross sections is made with reference to benzene 992 cm -1 Raman band whose absolute cross section is already known. On the premise that the samples and the reference are measured under exactly identical conditions and that the instrument response function of the spectrometer is known, the absolute Raman cross sections are determined by comparing the sample intensities with the reference. Absolute Raman cross sections of 28 organic molecules have been determined at 488 nm and 532 nm excitation and are present in this thesis. The contribution of pre-resonant effect is discussed for the determined Raman cross sections at different excitation wavelengths. Raman cross sections of phenylalanine residues in proteins are also determined and discussed in terms of the electrostatic effects from the environments.

並列關鍵字

Raman cross section ； Raman spectroscopy

參考文獻

1. Richard L. McCreery, Book: "Raman Spectroscopy for Chemical Analysis" Chapter 2 (2000)

2. Saito, Shigeki, Mitsuo Tasumi, and Conrad H. Eugster. "Resonance Raman spectra (5800–40 cm− 1) of All‐trans and 15‐cis isomers of β‐carotene in the solid state and in solution. Measurements with various laser lines from ultraviolet to red." Journal of Raman spectroscopy 14.5. 299-309 (1983).

3. Trulson, Mark O., and Richard A. Mathies. "Raman cross section measurements in the visible and ultraviolet using an integrating cavity: Application to benzene, cyclohexane, and cacodylate." The Journal of chemical physics 84.4. 2068-2074 (1986).

4. Hiro-o Hamaguchi, Koichi Iwata, Book:" 拉曼分光學 " [Raman spectroscopy (Chinese version)] translated by Yu-Shan, Huang (黃郁珊), TISRS & TARS 2016, Taiwan.

5. Abe, N., M. Wakayama, and M. Ito. "Absolute Raman intensities of liquids." Journal of Raman Spectroscopy 6.1. 38-41 (1977)