Jin Jin, Sioutis Ilias, Tarczay György, Gopalakrishnan Sandhya, Bezant Andrew, Miller Terry A
Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 West 18th Avenue, Columbus, Ohio 43210, USA.
J Chem Phys. 2004 Dec 15;121(23):11780-97. doi: 10.1063/1.1814104.
Dispersed fluorescence (DF) spectra of 1-propoxy, 1-butoxy, 2-propoxy, and 2-butoxy radicals have been observed under supersonic jet cooling conditions by pumping different vibronic bands of the B-X laser induced fluorescence excitation spectrum. The DF spectra were recorded for both conformers of 1-propoxy, three conformers of the possible five of 1-butoxy, the one possible conformer of 2-propoxy, and two conformers of the possible three of 2-butoxy. Analysis of the spectra yields the energy separations of the vibrationless levels of the ground X and low-lying A electronic state as well as their vibrational frequencies. In all cases, the vibrational structure of the DF spectra is dominated by a CO stretch progression yielding the nuCO stretching frequency for the X state and in most cases for the A state. In addition to the experimental work, quantum chemical calculations were carried out to aid the assignment of the vibrational levels of the X state and for some conformers the A state as well. Geometry optimizations of the different conformers of the isomers were performed and their energy differences in the ground states were determined. The results of the calculation of the energy separations of the close-lying X and A states of the different conformations are provided for comparison with the experimental observations.
在超声速喷射冷却条件下，通过泵浦B-X激光诱导荧光激发光谱的不同振转带，观测了1-丙氧基、1-丁氧基、2-丙氧基和2-丁氧基自由基的分散荧光（DF）光谱。记录了1-丙氧基两种构象、1-丁氧基可能的五种构象中的三种、2-丙氧基可能的一种构象以及2-丁氧基可能的三种构象中的两种的DF光谱。对光谱进行分析可得出基态X和低激发态A的无振动能级的能量间隔及其振动频率。在所有情况下，DF光谱的振动结构主要由CO伸缩振动序列主导，由此得出X态以及大多数情况下A态的νCO伸缩频率。除了实验工作外，还进行了量子化学计算，以辅助确定X态的振动能级，对于一些构象还包括A态的振动能级。对异构体的不同构象进行了几何优化，并确定了它们基态的能量差。提供了不同构象的近邻X态和A态能量间隔的计算结果，以便与实验观测结果进行比较。
