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Analytical derivative techniques for TDDFT excited-state properties:Theory and application

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Science China Chemistry 2014年第1期57卷 48-57页

作者： CHEN DanPing LIU Jie MA HuiLi ZENG Qiao LIANG wanzhen State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Hefei National Laboratory for Physical Science at Microscale University of Science and Technology of China Department of Chemical Physics University of Science and Technology of China

We review our recent work on the methodology development of the excited-state properties for the molecules in vacuum and liquid *** general algorithms of analytical energy derivatives for the specific properties such as the first and second geometrical derivatives and IR/Raman intensities are demonstrated in the framework of the time-dependent density functional theory(TDDFT).The performance of the analytical approaches on the calculation of excited-state energy Hessian has also been *** is found that the analytical approaches are superior to the finite-difference method on the computational accuracy and *** computational cost for a TDDFT excited-state Hessian calculation is only 2–3 times as that for the DFT ground-state Hessian *** the low computational complexity of the developed analytical approaches,it becomes feasible to realize the large-scale numerical calculations on the excited-state vibrational frequencies,vibrational spectroscopies and the electronic-structure parameters which enter the spectrum calculations of electronic absorption and emission,and resonance Raman spectroscopies for medium-to large-sized systems.

关键词： molecular excited-state properties,molecular Hessian,IR Raman intensities,the time-dependent density functional theory,analytical energy derivatives

Theoretical study of the low-lying electronic excited states for molecular aggregates

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Science China Chemistry 2013年第9期56卷 1258-1262页

作者： SHUAI ZhiGang LIU WenJian LIANG wanzhen SHI Qiang CHEN Hui MOE Key Laboratory of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua University Beijing National Laboratory for Molecular Sciences (BNLMS) Institute of Theoretical and Computational ChemistryState Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular Engineeringand Center for Computational Science and EngineeringPeking University Department of Chemistry Xiamen University Beijing National Laboratory for Molecular Science (BNLMS) Institute of ChemistryChinese Academy of Sciences

We present here a brief summary of a National Natural Science Foundation Major Project entitled "Theoretical study of the low-lying electronic excited state for molecular aggregates". The project focuses on theoretical investigation of the electronic structures and dynamic processes upon photo-and electric-excitation for molecules and aggregates. We aim to develop reliable methodology to predict the optoelectronic properties of molecular materials related to the electronic excitations and to apply in the experiments. We identify two essential scientific challenges: (i) nature of intramolecular and intermolecular electronic excited states; (ii) theoretical description of the dynamic processes of the coupled motion of electronic excitations and nucleus. We propose the following four subjects of research: (i) linear scaling time-dependent density-functional theory and its application to open shell system; (ii) computational method development of electronic excited state for molecular aggregates; (iii) theoretical investigation of the time evolution of the excited state dynamics; (iv) methods to predict the optoelectronic properties starting from electronic excited state investigation for organic materials and experimental verifications.

关键词： linear scaling TDDFT relativistic TDDFT excited-state dynamics theory molecular aggregates opto-electronic properties for organic materials charge mobility and exciton diffusion

One-pot/three-step synthesis of zinc-blende CdSe/CdS core/shell nanocrystals with thick shells

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Nano Research 2017年第4期10卷 1149-1162页

作者： Yuan Niu Chaodan Pu Runchen Lai Renyang Meng wanzhen Lin Haiyan Qin Xiaogang Peng Center for Chemistry of Novel and High-Performance Materials and Department of Chemistry Zhejiang University Hangzhou 310027 China

A one-pot/three-step synthetic scheme was developed for phase-pure epitaxy of CdS shells on zinc-blende CdSe nanocrystals to yield shells with up to sixteen monolayers. The key parameters for the epitaxy were identified, including the core nanocrystal concentration, solvent type/composition, quality of the core nanocrystals, epitaxial growth temperature, type/concentration of ligands, and composition of the precursors. Most of these key parameters were not influential when the synthetic goal was thin-shell CdSe/CdS core/shell nanocrystals. The finalized synthetic scheme was reproducible at an almost quantitative level in terms of the crystal structure, shell thickness, and optical properties.

关键词： zinc-blende core/shell quantum dots thick shells

ASRNet: Adversarial Segmentation and Registration Networks for Multispectral Fundus Images

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Computer Systems Science & Engineering 2021年第3期36卷 537-549页

作者： Yanyun Jiang Yuanjie Zheng Xiaodan Sui wanzhen Jiao Yunlong He Weikuan Jia School of Information Science and Engineering Shandong Normal UniversityJinan250358China Key Laboratory of Intelligent Computing&Information Security in Universities of Shandong Shandong Provincial Key Laboratory for Novel Distributed Computer Software TechnologyInstitute of Biomedical SciencesShandong Normal UniversityJinan250358China Shandong Provincial Hospital Affiliated to Shandong University Jinan250021China INSA Lyon University of LyonCNRSInsermVilleurbanne69621CedexFrance

Multispectral imaging (MSI) technique is often used to capture imagesof the fundus by illuminating it with different wavelengths of light. However,these images are taken at different points in time such that eyeball movementscan cause misalignment between consecutive images. The multispectral imagesequence reveals important information in the form of retinal and choroidal bloodvessel maps, which can help ophthalmologists to analyze the morphology of theseblood vessels in detail. This in turn can lead to a high diagnostic accuracy of several diseases. In this paper, we propose a novel semi-supervised end-to-end deeplearning framework called “Adversarial Segmentation and Registration Nets”(ASRNet) for the simultaneous estimation of the blood vessel segmentation andthe registration of multispectral images via an adversarial learning process. ASRNet consists of two subnetworks: (i) A segmentation module S that fulfills theblood vessel segmentation task, and (ii) A registration module R that estimatesthe spatial correspondence of an image pair. Based on the segmention-drivenregistration network, we train the segmentation network using a semi-supervisedadversarial learning strategy. Our experimental results show that the proposedASRNet can achieve state-of-the-art accuracy in segmentation and registrationtasks performed with real MSI datasets.

关键词： Deep learning deformable image registration image segmentation multispectral imaging(MSI)

Nonlinear adaptive control of generating set steam valve for power systems 36

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Nonlinear adaptive control of generating set steam valve for...

Theoretical investigation of the non-Condon effect on electron transfer:Application to organic semiconductor

第36届中国控制会议

作者： Qingyu Su wanzhen Quan Weiwei Quan School of Automation Engineering Northeast Electric Power University State Grid Power Supply Company of Anqing

ISBN: (纸本)9781538629185

As strongly nonlinear, dynamic,multidimensional and large scale systems, power systems in operation are always influenced by the external and internal disturbances;and thus the serious threat to stable operation of systems exists. In this paper, based on the three order mathematical model of single machine infinite systems with valve control and under the conditions that systems have unknown damping coefficient, Storage functions of control system are constructed on the basis of improved adaptive backstepping and Lyapunov methods. A nonlinear adaptive robust controller and a parameter update law are *** derived controller can not only ensure that the system states are bounded and keep the nonlinearity of power systems and the real-time parameter estimation but also improved the speed of parameter identification.

关键词： Power systems nonlinear improved adaptive backstepping Lyapunov parameter identification

来源： cnki会议评论

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Science China Chemistry 2011年第4期54卷 707-714页

作者： ZHANG WeiWei ZHAO Yi LIANG wanzhen State Key Laboratory for Physical Chemistry of Solid Surfaces Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Hefei National Laboratory for Physical Sciences at the Microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026China

The non-Condon effect plays an important role in the process of electron transfer (ET). Several theoretical models have been proposed to investigate its effect on ET rates. In this paper,we overview a theoretical method for the calculations of the non-Condon ET rate constants proposed by us,and its applications to organic semiconductors. First,full quantum expressions of the non-Condon ET rates are presented with the electronic couplings having exponential,Gaussian and linear dependences in terms of the nuclear coordinates,respectively. The proposed formulas have closed forms in time domain and they thus can be easily applied in multi-mode systems. Then,the driving force dependences of the ET rates involving the non-Condon effect are calculated with the use of full quantum mechanical formulas. It is found that these dependences show very different prop-erties from the Marcus one. As an example of applications,the approaches are used to investigate the non-Condon effect on the mobility of the organic semiconductor dithiophene-tetrathiafulvalene (DT-TTF). The results manifest that the non-Condon ef-fect enhances ET rates compared with the Condon approximation,and static fluctuations of electronic coupling dominate the ET rate in the DT-TTF,which has been confirmed by the molecular dynamics simulation.

关键词： electron transfer the Condon approximation non-Condon effect mobility molecular dynamics simulation

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In situ growth of large-area and self-aligned graphene nanoribbon arrays on liquid metal

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National Science Review 2021年第12期8卷 37-45页

作者： Le Cai wanzhen He Xudong Xue Jianyao Huang Ke Zhou Xiahong Zhou Zhiping Xu Gui Yu Beijing National Laboratory for Molecular Sciences CAS Research/Education Centre for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of Sciences School of Chemical Sciences University of Chinese Academy of Sciences Applied Mechanics Laboratory Department of Engineering Mechanics and Centre for Nano and Micro MechanicsTsinghua University

Intrinsic graphene features semi-metallic characteristics that limit its applications in electronic devices,whereas graphene nanoribbons(GNRs) are promising semiconductors because of their bandgap-opening feature. However, the controllable mass-fabrication of high-quality GNR arrays remains a major *** particular, the in situ growth of GNR arrays through template-free chemical vapor deposition(CVD) has not been realized. Herein, we report a template-free CVD strategy to grow large-area, high-quality and self-aligned GNR arrays on liquid copper surface. The width of as-grown GNR could be optimized to sub-10 nm with aspect ratio up to 387, which is higher than those of reported CVD-GNRs. The study of the growth mechanism indicates that a unique comb-like etching-regulated growth process caused by a trace hydrogen flow guides the formation of the mass-produced self-aligned GNR arrays. Our approach is operationally simple and efficient, offering an assurance for the use of GNR arrays in integrated circuits.

关键词： graphene nanoribbons template-free chemical vapor deposition comb-like etching self-alignment in situ growth

Switching on/off phosphorescent or non-radiative channels by aggregation-induced quantum interference

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Aggregate 2024年第1期5卷 175-184页

作者： Yi Kong Yu-Chen Wang Xunkun Huang wanzhen Liang Yi Zhao Department of Chemistry State Key Laboratory of Physical Chemistry of Solid SurfacesiChEMFujian Provincial Key Laboratory of Theoretical and Computational Chemistryand College of Chemistry and Chemical EngineeringXiamen UniversityXiamenPeople’s Republic of China

Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in *** crucial design principle for such materials is to suppress as much as possible the non-radiative decay of the triplet exciton while maintaining a moderate phosphorescent radiative ***,molecular engineering often exhibits similar regulation trends for the two ***,we propose that the quantum interference caused by aggregation can be utilized to control the phosphorescent and non-radiative decay *** systematically analyze various constructive and destructive transition pathways in aggregates with different molecular packing types and establish clear relationships between the luminescence characters and the signs of the singlet and triplet excitonic *** is shown that the decay channels can be flexibly switched on or off by regulating the packing type and excitonic *** importantly,an enhanced phosphorescent decay and a completely suppressed non-radiative decay can be simultaneously realized in the aggregate packed with inversion *** work lays the theoretical foundation for future experimental realization of quantum interference effects in phosphorescence.

关键词： excitonic coupling intersystem crossing organic aggregates organic room temperature phosphorescence quantum interference

The Development of Molecularly Imprinted Polymers in the Clean-Up of Water Pollutants: A Review

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American Journal of Analytical Chemistry 2019年第5期10卷 202-226页

作者： Kwabena Agyarko Sarpong wanzhen Xu Weihong Huang Wenming yang School of the Environment and Safety Engineering Jiangsu University Zhenjiang China School of Materials Science and Engineering Jiangsu University Zhenjiang China

In the last decades, the extensive use of chemical and biological materials has not only seen to an increased transport of environmental pollutants but also, it has interfered and compromised the pristine state of different environmental matrices with emphasis on waterbodies. This has stimulated studies to develop and adopt novel techniques which consider the removal of pollutants with premium on economic feasibility, simple instrumentation, and high performance. In the treatment of water, the removal of trace concentration organic compounds and other numerous polluted water effluents is difficult due to limited affinity of trace compound ions to ion exchange resins. Because of the selective nature;recognition properties;adsorption ability;high stability;and easier preparation of molecular imprints, they are considered attractive and suitable artificial receptors to be applied in analytical separations, drug delivery, and as chemical sensors. In this review, we touch on the fundamentals of molecularly imprinted technologies and underscore some recent advances made in the development of imprinted polymers that are compatible with water and how they can be used in the clean-up of pollutants. The paper finally presents a comprehensive report on some challenges and outlook in the use of MIPs as water treatment sorbent.

关键词： Wastewater Treatment Aqueous Conditions Molecularly Imprinted Polymers Water-Compatible