Femtosecond time-resolved fluorescence depletion spectroscopy was used in the study of the orientation relaxation of Rhodamine 700(LD700) and Oxazine 750(OX750) in DMSO. The anisotropy functions of the dye molecules were obtained from the fluorescence depletion spectra, as the polarization of probe pulse is parallel and perpendicular respectively. The results show that the transition dipole moment of the pump and the probe of LD700 and OX750 are parallel. The time constants of the orientation relaxation of these dye molecules in DMSO are 1.8 and 1.9 ps for LD700 and OX750, respectively.
团簇是由原子或分子组成的聚合体,它们的成键包括从弱的van der Waals力、氢键到强的离子键、金属键、共价键和配位键。在原子、分子向凝聚态转变过程中,团簇的形成和增长起着核心的作用。通常利用分子束和激光气化固体样品等动力学方法可以产生各种团簇。尽管实验上可以控制产生各种团簇,但是许多团簇通常不是热力学上稳定的物种并且极易发生解离和增长反应,这样形成的一系列团簇不仅是瞬态存在的而且浓度也低,因此化学上分离团簇是比较困难的;虽然团簇的组成利用质谱方法容易指认。
