Vacuum ultraviolet absorbance of alkanes: an experimental and theoretical investigation
Vacuum ultraviolet absorbance of alkanes: an experimental and theoretical investigation
复制标题
烷烃的真空紫外吸收：实验和理论研究
作者：
J. X. Mao;P. Kroll;K. Schug
众所周知，烷烃的电子吸收光谱很宽，缺乏离散的能带结构。以前的研究表明，他们的HOMO-LUMO能隙可以用来理解这些光谱的吸收边缘。随着新的台式真空紫外(VUV)光谱吸收检测器的出现，现在可以更方便地在惰性气体相环境下收集更大范围的结构的VUV吸收光谱(从120到240 nm)。使用新的扩展的实验VUV光谱数据和理论量子力学计算的组合，重新验证了以前报道的假设，并探索了其极限。研究指出，烷烃的第一个强激发并不总是HOMO-LUMO转变。因此，烷烃的HOMO-LUMO能隙不能直接作为一个普遍而可靠的参数来理解它们的实验吸收边。报道了多种烷烃结构的真空紫外光谱数据，并讨论了这些结构与光谱之间的关系。
The electronic absorption spectra of alkanes are known to be broad and lack discrete band structures. Previous studies have suggested their HOMO-LUMO energy gaps could be used to understand the absorbance edges of these spectra. With the advent of a new benchtop vacuum ultraviolet (VUV) spectroscopic absorption detector, it is now possible to collect VUV absorption spectra (from 120 to 240 nm) for an extended range of structures under an inert gas phase environment more conveniently. The previously reported hypothesis was revisited and its limits were explored using a combination of new extended experimental VUV spectral data and theoretical quantum mechanics calculations. It was pointed out from this study that the first strong excitations of alkanes are not always the HOMO-LUMO transition. As a result, the HOMO-LUMO energy gap of alkanes should not be used directly as a universal and reliable parameter to understand their experimental absorbance edges. VUV spectral data for a larger variety of alkanes structures were reported and the relation between these structures and spectra was discussed.