Flakus Henryk T, Hachuła Barbara, Hołaj-Krzak Jakub T
Institute of Chemistry, University of Silesia, 9 Szkolna Street, Pl-40-006 Katowice, Poland.
Institute of Chemistry, University of Silesia, 9 Szkolna Street, Pl-40-006 Katowice, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 May 5;142:126-34. doi: 10.1016/j.saa.2015.01.074. Epub 2015 Feb 7.
The spectral properties of four different crystalline succinic acid (HOOC-(CH2)2-COOH) (SAC) isotopomer systems, h6, d2, d4 and d6, were examined by means of the IR spectroscopy in polarized light aided by numerical simulations of the νO-H and νO-D band contour shapes on utilizing the "strong-coupling" model. The abnormal IR spectral properties of SAC crystals in relation to the corresponding properties of glutaric, pimelic and adipic acid crystals were ascribed to the hyperconjugation electronic effects in the acid associated molecules. A vibronic coupling mechanism involving the proton stretching vibrations in the (COOH)2 cycles and the electronic motions in the molecular skeletons, the isotopic "H/D self-organization" mechanisms and a long-distance vibrational exciton coupling between the adjacent (COOH)2 cycles in the molecular chains are mainly responsible for the generation of the temperature effects in the crystalline IR spectra.
通过红外光谱法在偏振光下，借助利用“强耦合”模型对νO-H和νO-D带轮廓形状进行数值模拟，研究了四种不同的结晶琥珀酸（HOOC-(CH2)2-COOH）（SAC）同位素异构体系统h6、d2、d4和d6的光谱特性。SAC晶体相对于戊二酸、庚二酸和己二酸晶体的相应特性的异常红外光谱特性归因于酸缔合分子中的超共轭电子效应。一种涉及(COOH)2环中质子拉伸振动和分子骨架中电子运动的振动耦合机制、同位素“H/D自组织”机制以及分子链中相邻(COOH)2环之间的长距离振动激子耦合，主要负责晶体红外光谱中温度效应的产生。
