Dengl Armin, Beyer Rebecca, Peterseim Tobias, Ivek Tomislav, Untereiner Gabriele, Dressel Martin
1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
J Chem Phys. 2014 Jun 28;140(24):244511. doi: 10.1063/1.4884964.
The neutral-to-ionic phase transition in the mixed-stack charge-transfer complex tetrathiafulvalene-p-chloranil (TTF-CA) has been studied by pressure-dependent infrared spectroscopy up to p = 11 kbar and down to low temperatures, T = 10 K. By tracking the C=O antisymmetric stretching mode of CA molecules, we accurately determine the ionicity of TTF-CA in the pressure-temperature phase diagram. At any point, the TTF-CA crystal bears only a single ionicity; there is no coexistence region or an exotic high-pressure phase. Our findings shed new light on the role of electron-phonon interaction in the neutral-ionic transition.
通过高达(p = 11)千巴且低至低温(T = 10)K的压力依赖红外光谱，研究了混合堆积电荷转移复合物四硫富瓦烯-对氯苯醌（TTF-CA）中的中性到离子相转变。通过追踪CA分子的(C=O)反对称伸缩模式，我们在压力-温度相图中准确确定了TTF-CA的离子性。在任何一点，TTF-CA晶体仅具有单一离子性；不存在共存区域或奇异的高压相。我们的发现为电子-声子相互作用在中性-离子转变中的作用提供了新的见解。
