Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
J Phys Chem B. 2009 Nov 19;113(46):15382-91. doi: 10.1021/jp9069256.
Nearly degenerate asymmetric stretches with perpendicular transition dipole moments of the deuterated guanidinium cation (DGdm(+)) in D(2)O and D-glycerol/D(2)O mixtures at 1600 cm(-1) were investigated by linear FTIR spectroscopy and polarization dependent femtosecond pump-probe spectroscopy. The vibrational coupling of the asymmetric stretches of guanidinium occurs within 0.5 ps and leads to fast decay of the anisotropy to a level of 0.1. A systematic study of the influence of the coherence transfer on pump-probe signals is given. Following this decay, the anisotropy decays with a time constant of 4.1 ps in D(2)O by rotational diffusion about an axis perpendicular to the DGdm(+) mean plane. The presence of aggregation was demonstrated for concentrations higher than 0.2 M.
通过线性傅里叶变换红外光谱和偏振相关飞秒泵浦探针光谱研究了在 1600cm(-1)处氘代胍鎓阳离子（DGdm(+)）在 D(2)O 和 D-甘油/D(2)O 混合物中的近乎简并不对称伸缩，具有垂直跃迁偶极矩。胍鎓的不对称伸缩的振动耦合在 0.5 ps 内发生，并导致各向异性快速衰减至 0.1 水平。给出了对泵浦探针信号的相干转移影响的系统研究。在此衰减之后，各向异性通过 DGdm(+)平均平面垂直的轴的旋转扩散以 4.1 ps 的时间常数在 D(2)O 中衰减。对于浓度高于 0.2 M，证明了聚集的存在。
