Laser-Induced Fluorescence Spectroscopy of Large Secondary Alkoxy Radicals: Part I. Spectral Overviews and Vibronic Analysis
Laser-Induced Fluorescence Spectroscopy of Large Secondary Alkoxy Radicals: Part I. Spectral Overviews and Vibronic Analysis
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大仲烷氧基自由基的激光诱导荧光光谱：第一部分：光谱概述和电子振动分析
DOI：
10.1021/acs.jpca.0c10662
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Miller, Terry A.
中科院分区：
文献类型：
--
作者：
Liu, Jinjun;Miller, Terry A.
本文报道了喷射冷却C5-C10仲烷氧基自由基的振动分辨激光诱导荧光光谱。LIF光谱表明振动结构类似于较小的（C3-C4）仲烷氧基。对于2-戊氧基和2-己氧基，旋转分辨LIF光谱也已记录。在每个分子的电子振动带中观察到两种类型的转动结构。对2-戊氧基和2-己氧基进行了广泛的量子化学计算。计算结果包括构象异构体的相对能量、几何构型以及近简并的A <$和X <$电子态之间的能量分离（ΔEA <$-X <$）。根据不同仲烷氧基的电子振动结构之间的相似性和计算的分子参数，包括构象异构体的相对能量、B跃迁频率和振动频率，LIF光谱中的强电子振动带被归属于每个仲烷氧基的两个最低能量构象异构体的起源带和CO伸缩带. 2-戊氧基和2-己氧基的两种不同构象的不同旋转结构将在本系列的第二部分中进行模拟和分析（J. Phys. Chem. A2021，DOI：10.1021/acs.jpca.0c10663）。
We report vibronically resolved laser-induced fluorescence (LIF) spectra of jet-cooled C5–C10 secondary alkoxy radicals. The LIF spectra demonstrate vibronic structures similar to smaller (C3–C4) secondary alkoxies. For 2-pentoxy and 2-hexoxy, rotationally resolved LIF spectra have also been recorded. Two types of rotational structures have been observed in vibronic bands of each molecule. Extensive quantum chemistry calculations have been performed on 2-pentoxy and 2-hexoxy. The computed results include the relative energies of conformers, their geometries, and the energy separations between the nearly degenerateÃandX̃electronic states (ΔEÖX̃). Based on the similarity between the vibronic structures of different secondary alkoxies and calculated molecular parameters, including the relative energies of conformers, theB̃←X̃transition frequencies, and the vibrational frequencies, strong vibronic bands in the LIF spectra are assigned to the origin bands and CO stretch bands of the two lowest-energy conformers of each secondary alkoxy radical. The distinct rotational structures of the two different conformations of 2-pentoxy and 2-hexoxy will be simulated and analyzed in Part II of this series (J. Phys. Chem. A2021, DOI: 10.1021/acs.jpca.0c10663).