Gadomski W, Polok K, Skała K, Ratajska-Gadomska B
Faculty of Chemistry, University of Warsaw, Ul. Żwirki I Wigury 101, 02-089, Warsaw, Poland.
Anal Sci. 2025 Mar;41(3):211-224. doi: 10.1007/s44211-024-00702-8. Epub 2024 Dec 16.
The femtosecond pump-probe technique, i.e. the transient transmission spectroscopy, has been used for the first time, to detect the vibrational spectra of symmetric fundamentals ν and ν in bromoform and chloroform. The spectra were obtained by fast Fourier transforms of the time domain signals. For both, CHCl and CHBr, there are four isotopologues contributing to the spectra, due to the existence of two stable isotopes; chlorine, Cl and Cl, and bromine, Br and Br, respectively. While for chloroform the isotope splitting of the ν spectral band can be observed even in the spontaneous Raman scattering, for bromoform it is not detectable. Herewith we show that using the time domain spectroscopy and the windowed Fourier transform method we can provide the high resolution spectrum of the ν fundamental in bromoform, in which the contributions of all isotopologues are well distinguishable. The data have been collected for few volume concentrations of the studied liquids diluted in the neutral solvent CCl. It is shown that the intensity pattern of the spectra evolves with decreasing concentration and for the ν fundamental it reaches the natural abundance pattern at a very high dilution. The simple theoretical model, which treats the molecules in a liquid as interacting oscillators, allows us to explain the dependence of the shape of the spectrum on the strength of the intermolecular interactions.
飞秒泵浦 - 探测技术，即瞬态透射光谱法，首次被用于检测溴仿和氯仿中对称基频ν和ν的振动光谱。光谱通过对时域信号进行快速傅里叶变换获得。对于CHCl₃和CHBr₃，由于分别存在两种稳定同位素氯（³⁵Cl和³⁷Cl）和溴（⁷⁹Br和⁸¹Br），有四种同位素异构体对光谱有贡献。虽然对于氯仿，即使在自发拉曼散射中也能观察到ν光谱带的同位素分裂，但对于溴仿则无法检测到。在此我们表明，使用时域光谱法和加窗傅里叶变换方法，我们可以提供溴仿中ν基频的高分辨率光谱，其中所有同位素异构体的贡献都能很好地区分。已收集了在中性溶剂CCl₄中稀释的几种体积浓度的研究液体的数据。结果表明，光谱的强度模式随浓度降低而演变，对于ν基频，在非常高的稀释度下达到天然丰度模式。将液体中的分子视为相互作用的振荡器的简单理论模型，使我们能够解释光谱形状对分子间相互作用强度的依赖性。
