烯烃聚合数学模拟研究与现状

综述了近年来国内外在烯烃聚合微观形态和宏观反应器数学模拟方面取得的研究成果，指出了烯烃聚合过程数学模拟的发展方向。     

自蔓延波聚合研究进展

波聚合是指靠自身反应放热产生的热波维持反应进行而将单体转化为聚合物的聚合方法。由于波聚合不需要外界持续供热、无溶剂排放和反应设备简单,是一种节能无污染的低成本材料制备工艺,极具应用前景。本文综述了从发现波聚合至今已取得的研究成果,包括波聚合机理、聚合波产生并自蔓延的条件、波结构、传播速度、传播模式以及产物特征,并对波聚合工艺用于高分子材料的制备进行了评述。     

波聚合体系、引发、过程及应用

波聚合是一种通过局部反应区域向未反应区域连续移动将单体转化为聚合物的反应模式,具有简便快速、节能降耗和产物性能优异等优势,是化学合成、功能材料与结构材料制备的新方法。本文对波聚合反应体系、引发、过程、应用及存在问题等方面进行综述。重点评述了新型波聚合体系如二元或多元体系、离子液体体系、深共晶溶剂体系等;新型引发剂如光引发剂和离子液体引发剂等特殊引发剂;波聚合反应体系中的助剂如填料、交联剂、链转移剂、活化剂、增稠剂、表面活性剂和催化剂等对聚合过程和产物结构性能的影响;新发展的引发方式如紫外线、水、等离子体和耦合引发等;以及特殊波聚合过程。最后,展望了波聚合存在问题和商业化应用的研究方向。     

非绝热分子动力学进展

本文结合作者近年来来在光化学周环反应研究方面的工作，对非绝热分子动力学的基本理论模型和研究现关夜较全面的介绍，重点讨论经典轨迹在单分子衰变和离解、碰撞猝灭、光化学周环反应、非绝热电子转移等理论研究中的应用。     

[2＋4]光环加成中的非绝热相互作用

The S1→S0 nonadiabatic coupling terms are calculated for different reaction modes of concerted [2 + 4] photocycloadditions in the Huckel-Hubbard approximation. The nonadiabatic transition probabilities are estimated by means of the Landau-Zener model as well. The calculated nonadiabatic coupling terms and transition probabilities show clearly the differences between the nonadiabatic interactions of the two reaction modes s+a (or a+s) and s+s. With these calculated results the stereospecifities in concerted [2+4] photocycloadditions are correctly predicted.     

非绝热量子散射动力学

综述了非绝热化学过程的研究,着重介绍了含时波包非绝热量子动力学方法,以及在化学反应中的非绝热动力学、光解非绝热动力学及非绝热传能过程的应用.     

用绝热量热法研究自由基聚合动力学

该文用Dewar聚合釜研究均相自由基聚合动力学 ,并测定动力学和热力学有关参数 .先用动力学机理已知的甲基丙烯酸甲酯 (MMA)或苯乙烯 (St) / 2 ,2′ 偶氮二 ( 2 ,4 二甲基戊腈 ) (DAVN) /甲苯系统验证绝热量热法的可靠性 ,再用该法研究了动力学机理未知的系统 ,氯化二烯丙基二甲基铵 (DADMAC) / 2 ,2′ 偶氮双(氯化 2 丙基铵 ) /水体系 .用所测动力学和热力学参数计算而得的结果与实验值吻合良好 ,且所测MMA和St的有关参数与文献值也能吻合 .     

防晒化合物咖啡酸的直接-非绝热动力学（英文）

作为防晒霜中一种广泛使用的成分,咖啡酸具有很强的紫外线吸收能力.本文通过研究咖啡酸的光诱导动力学,探讨其光保护机制.在半经验电子结构理论水平上使用直接面跳跃模拟方法研究最稳定的咖啡酸异构体非绝热动力学.从不同电子态开始进行动力学模拟,探讨光诱导反应通道对激发波长的依赖性.结果表明,氢原子解离和环变形驱动的通道主导了咖啡酸的非绝热动力学.同时改变激发波长会调控通道的分支比例,本研究揭示了咖啡酸化合物光保护原理的分子机制.     

多原子体系非绝热动力学的近似理论方法

非绝热动力学普遍存在于光物理和光化学过程中。描述非绝热跃迁需要处理电子-原子核间的相互耦合运动。由于计算量随体系尺度增大剧烈增长,准确的量子动力学计算目前只适用于描述小分子体系。为了研究多原子分子体系的非绝热过程,近年来发展了一些基于量子-经典动力学近似方法。本文将对典型的这类方法包括经典Ehrenfest方法、面跳跃方法、基于Wigner表示的混合量子-经典方法进行简要的介绍,并讨论如何将量子-经典动力学方法与电子结构从头算手段相结合,模拟非绝热过程。重点阐明各种方法的基本思想和优缺点,并对该领域的发展进行展望。     

烯烃易位聚合研究新进展环烯烃开环易位聚合和非环二烯易位聚合

本文综述了近年来环烯烃开环易位聚合和非环二烯易位聚合研究新进展，并以活性开环易位聚合催化剂作了详细概述。     

Non-adiabatic molecular dynamics simulation of ultrafast solar cell electron transfer

A non-adiabatic (NA) molecular dynamics (MD) simulation of the photoinduced electron transfer (ET) from a molecular electron donor to the TiO₂ acceptor is carried out. The system under study is typical of the dye sensitized semiconductor nanomaterials used in solar cells, photocatalysis and photoelectrolysis. The electronic structure of the dye-semiconductor system and the adiabatic dynamics are simulated by ab initio density functional theory MD, while the NA effects are incorporated by the quantum-classical mean-field approach. A novel procedure separating the NA and adiabatic ET pathways is developed. The simulation provides a detailed picture of the ET process. For the specific system under study, ET occurs on a 30 fs time scale, in agreement with the ultrafast experimental data. Both adiabatic and NA pathways for the ET are observed. The NA transfer entirely dominates at short times and can occur due to strong localized avoided crossing as well as extended regions of weaker NA coupling. Although the adiabatic ET contribution accumulates more slowly, it approaches that of the NA ET pathway asymptotically. The electron acceptor states are formed by the d-orbital of Ti atoms of the semiconductor and are localized within the first 3–4 layers of the surface. About 20% of the acceptor state density is localized on a single Ti atom of the first surface layer. The simulation predicts a complex non-single-exponential time dependence of the ET process.     

工业丙烯聚合过程的模型化研究进展

基于我国聚丙烯生产状况,指出我国在聚丙烯合成技术上的研究缺陷.针对国内缺陷并遵循"聚丙烯合成过程模型化"主线,本文从聚丙烯生产工艺、丙烯聚合机理、丙烯聚合动力学以及聚合反应器模型四方面对丙烯聚合过程模型化的近期研究进展进行综述,重点简述我国科研工作者在相关方面的研究进展.     

Theories and Applications of Mixed Quantum-Classical Non-adiabatic Dynamics

Electronically non-adiabatic processes are essential parts of photochemical process, collisions of excited species, electron transfer processes, and quantum information processing. Various non-adiabatic dynamics methods and their numerical implementation have been developed in the last decades. This review summarizes the most significant development of mixed quantum-classical methods and their applications which mainly include the Liouville equation, Ehrenfest mean-field, trajectory surface hopping, and multiple spawning methods. The recently developed quantum trajectory mean-field method that accounts for the decoherence corrections in a parameter-free fashion is discussed in more detail.     

Non-adiabatic dynamics of pyrrole: Dependence of deactivation mechanisms on the excitation energy

Non-adiabatic dynamics simulations were performed for pyrrole at time-dependent density functional theory level using the trajectory surface hopping approach. Initial conditions were prepared based on the UV-absorption spectrum so as to simulate monochromatic absorption in three distinct spectral regions. The results showed predominance of the NH-stretch mechanism for excited-state relaxation. With increasing initial energy, however, other mechanisms are activated as well, even though they still occurred for a minor fraction of the trajectories. Dynamics starting at the origin of the absorption spectrum exhibited internal conversion to the ground state with a time constant of 20 fs. In contrast, dynamics starting at higher energies gave rise to much longer time constants for internal conversion near 200 fs.     

线型缩聚反应的计算机模拟

缩聚反应是一类重要的高分子合成方法。其中最简单的反应为线型缩聚体系,它可分为两类,分别是含有两个可缩合的官能团的单体或单体对进行的相互缩合的体系。Flory在上世纪四十年代采用统计方法对该缩聚体系做过系统的理论研究,并在官能团等活性的假定下提出了著名的Flory分布函数,由此揭示了反应体系中数均聚合度xn、重均聚合度xw、不同聚合度分子的分布情况与反应程度p的关系。本文利用计算机模拟的方法,同样在官能团等活性的假定下模拟了线性缩聚反应的全反应过程,所得到的结果与用统计方法所得到的结果完全一致。本方法是对整个真实反应过程的直观模拟,对研究相似的以逐步聚合反应机理进行的反应具有普适性,并具有可拓展到模拟更真实的粘性聚合体系以及研究反应动力学的潜力。     

Ultrafast Spectroscopic Study on Non-adiabatic UV Protection Mechanism of Hemicyanines

In this work, we firstly elucidated the ultraviolet light protection dynamics mechanism of the typical hemicyanines, i.e.. Hemicy and DHemicy, by combining the theoretical calculation method and the transient absorption spectra. It is theoretically and experimentally demonstrated that both Hemicy and DHemicy have strong absorption in UVC (200-280 nm), UVB (280-300 nm), and UVA (320-400 nm) regions. Moreover, after absorbing energy, Hemicy and DHemicy can jump into the excited states. Subsequently, Hemicy and DHemicy relax to \begin{document}$\mathrm{S}_0 $\end{document} states from \begin{document}$\mathrm{S}_1 $\end{document} states rapidly by the non-adiabatic transition at the conical intersection point between the potential energy curves of \begin{document}$\mathrm{S}_1 $\end{document} and \begin{document}$\mathrm{S}_0 $\end{document} states, and are accompanied by the trans-cis photoisomerism. The transient absorption spectra show that trans-cis photoisomerization occur within a few picoseconds. Thus, the ultraviolet energy absorbed by Hemicy and DHemicy could be relaxed ultrafastly by the non-adiabatic trans-cis photoisomerization processes.     

原子转移自由基聚合的动力学模型化研究

原子转移自由基聚合(ATRP)是“活性”/可控自由基聚合方法中研究最为广泛的一种,它不仅适用单体广泛、反应条件温和,而且可以方便地对聚合物进行结构设计.为了能够更深入地了解和控制聚合过程,通过ATRP动力学模型化并耦合不同操作方式下的反应器模型已成为必然,它可以更精确地控制大分子链结构,如分子量及其分布、共聚组成及组成分布,同时还能优化聚合条件.从传统自由基聚合理论入手并结合ATRP与传统 自由基聚合的异同,本文首先论述了ATRP动力学模型化过程;其次系统综述了已有的ATRP动力学模型研究,着重对三类不同的数学模型处理方法(矩方法,蒙特卡罗法、商业软件包-PREDICI,GEPASI等)进行了总结.     

半连续乳液聚合动力学模型

介绍半连续乳液聚合动力学模型的研究进展及建模方法，归结出３种形式模型，基础模型，具体模型与通用模型，指出通常从一些假定出发，根据质量平衡，能量平衡反应机理建立模型方程，通过模型参数估计，已有模型参数的利用及模型变量的求取，使用数值方法求解模型。     

嵌段共聚物在乳液聚合和分散聚合中的应用

综述了嵌段共聚物在乳液聚合和分散聚合中作为稳定剂应用的进展，主要讨论了共聚物化学组成，比例，分子量，浓度以及胶束形成等因素对聚合体系的影响。