面向复杂体系光谱计算的多尺度理论模型及计算方法的发展和应用

The progress of theoretical and computational methods for the optical spectra of complex systems falls largely behind the innovation of lasers and spectral instruments. Therefore, the current theoretical and computational methods present a substantial challenge when they are applied to calculate the spectra of complex systems which are interesting to the current scientific and technological research. This project aims to develop or improve the relevant electronic structure theory and quantum dynamics methods for the vibrational and vibronic spectra, such as the vibrationally-resolved electronic spectra and resonance Raman spectra, of biological systems, molecular aggregates, and hybird molecule/semiconductor–noble metal nanoparticles. In quantum dynamics, the project will derive the spectral differential cross sections in time domain with inclusion of the mode-mixing,Franck-Condon (FC) and Herzberg-Teller(HT) effects. In the electronic structure theory, the project will further develop or improve the analytic geometric derivative approaches for the ground- and excited-state energies and the one- or two-photon transition tensors within the framework of density functional theory (DFT) and time-dependent density functional theory (TDDFT); realize the pallelization of developed codes and linear scaling calculations; further develop the hybrid quantum-classical methods, especially those based on TDDFT, for the systems embodied in the condensed-phase environments; build the effective model Hamiltonian for the systems with exciton-exciton or exciton-plasmon interactions. At the end, the computationally efficient and user-friendly program packages for the computation of vibrarional and vibronic spectra will be constructed. Finally, the project will efficiently connects the developed quantum dynamics and electronic structure methods with the classical molecular mechanics or polarizable continuum solvent model or electromagnetic theory to achieve the multi-scale simulations for realistic biological systems, organic solar cells and molecule-noble metal nanoparticles, reveal their photophysical properties.

将当代理论计算方法用于计算当前科学及技术感兴趣的复杂体系的光谱时面临巨大挑战。本项目将致力于发展和改进与复杂体系光谱计算相关的电子结构理论及量子动力学计算方法，特别是发展快速的理论计算方法和程序去计算生物大分子、分子聚集体、分子/半导体-贵金属纳米粒子等体系的振动谱、振动精度的电子谱及共振拉曼谱等。在量子动力学方面，拟进一步发展包含FC、HT、模混合效果的时间相关函数方法去计算谱微分截面。在电子结构方面将进一步发展和改进基于DFT/TDDFT 的基态、激发态能量及跃迁偶极对核坐标的解析导数方法；将已建立的程序并行和实现线性标度算法；发展量子-经典组合方法去描述镶嵌于凝聚环境中体系的基、激发态几何和电子结构，电-声耦合强度等；构建激子-激子、激子-等离子激元间相互作用的有效模型哈密顿；建立高效的计算软件，并用于描述光合作用体系、有机太阳能电池、分子/半导体-金属纳米粒子等体系的光物理性质。

项目基于电子结构理论、计算电动力学和量子动力学方法发展快速有效的、适合于复杂分子和分子聚集体光谱计算及光化学过程描述的理论计算方法和程序，并应用研究贵金属纳米粒子的表面增强行为、有机分子和无机纳米粒子聚集体中的激子动力学，及预测及调控新型功能材料的性能等方面。项目执行期间在下面几个方向取得了重要进展：（1）继续发展了含时相关函数方法去计算处于复杂环境中分子的vibronic谱，特别是结合等离激元的多极展开量子模型，发展了一种可以同时考虑plasmon-exciton耦合和电-声相互作用的光谱计算方法，此方法可以通过简单地调节plasmon-exciton耦合强度或plasmon damping率来产生从Fano反共振到Rabi分裂的所有谱线型；（2）发展量子-经典组合的方法或利用等离激元的多极展开量子模型或计算电动力学模型去研究分子-MNP 体系的线性和非线性光谱、研究plasmon-mediated激子动力学行为及纳米粒子聚集体的量子行为；（3）利用电子结构理论构造模型Hamiltonian、含时波包扩散描述态演化，探索了发生于有机分子聚集体中的单态裂分过程中涉及的量子干涉及激子相干行为与聚集体的聚集行为的关系，及它们对分裂速率的影响，这对实验合成和调控裂分效率提供了理论指导；（4）理论研究了荧光蛋白质（FPs）的光物理、光化学过程和有机-无机杂化钙钛矿半导体材料的构-效关系等，设计了两种结构范式下热激活延迟荧光蓝光发射体；揭示了一种红色 FP中Stokes shift 的起源，黄色RP中单、双光子吸收极大峰不重叠的起因、以及二维钙钛矿的性质随层数变化的关系等等。项目开展期间共发表标注论文26篇，培养学生11人（博士毕业6人， 硕士毕业5人），资助参加了大哟12次国际或双边学术会议，协助主办了2019年12月在厦门召开的“复杂体系激发态电子结构理论及动力学方法”的国际研讨会。