光解瞬态自由基化学诱导动态电子极化(CIDEP)的四种机理

化学诱导动态电子自旋极化(CIDEP)来源于顺磁粒子在其自旋能级间的非Boltzmann分布,主要有四种形成机理即三重态机理(TM)、自由基对机理(RPM)、自旋相关自由基对机理(SCRP)、自由基-三重态对机理(RTPM).本文系统地介绍了这四种机理的概念和相应的物理和化学过程,列出了每种机理的极化强度表达式,分析了每种机理产生的CIDEP谱的典型特征并给出了代表性的实验谱线.     

自旋相关自由基对电子极化机理的理论计算

利用自由基对自旋哈密顿，考虑自由基对自旋三重态中的态与自旋单重态的相互作用，理论上计算了自旋相关自由基对的能级及其波函数，并从密度矩阵运动计算了动态电子极化跃迁的度。     

国内CIDEP研究进展

化学诱导动态电子极化（CIDEP）是检测瞬态顺磁粒子并表征其特征的强有力的手段,对于研究光化学和光物理瞬态过程的微观机理和规律有重要意义. 本文较为详细地总结了4种常见的CIDEP机理,讨论了各种极化谱及相应的极化条件;简要介绍了国内研究小组在CIDEP理论以及在均相溶液和微复相体系中光化学过程的CIDEP研究成果.      

Determination of solubility parameters of cross-linked macromonomeric initiators based on polypropylene glycol

A new type macromonomeric azo initiators also named macroinimers, MIMs, based on polypropylene glycol, PPG, with molecular weight 400 and 2000, were synthesized. Self-condensing radical polymerization of the macroinimers gave cross-linked polypropylene glycols. The solubility parameters of the cross-linked polymers determined using swelling experiments in a series of solvents have been reported. Crosss-linked PPG-400 and cross-linked PPG-2000 indicated the same solubility parameter value. But their swelling ratios were different because of the differences of the chain lengths in between of the cross-points (Mc) of the gels. Therefore, while the largest swelling ratio exhibited by a cross-linked PPG-2000 in tetrahydrofurane was being 19.48, this ratio was 6.84 for the cross-linked PPG-400 in the same solvent. The solubility parameters and constant α for these cross-linked polymers were obtained as δ_{cross-linked PPG-400} = 9.56 (cal cm⁻³)^1/2, α = 0.123 cm³ cal⁻¹ and δ_{cross-linked PPG-2000} = 8.95 (cal cm⁻³)^1/2, α = 0.107 cm³ cal⁻¹ by using the least squares regression method.