Philosophical Transactions of the Royal Society A最新文献_第3页

Theoretical perspectives on non-Born–Oppenheimer effects in chemistry 化学中非玻恩-奥本海默效应的理论展望

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-28 DOI: 10.1098/rsta.2020.0377

S. Hammes‐Schiffer

{"title":"Theoretical perspectives on non-Born–Oppenheimer effects in chemistry","authors":"S. Hammes‐Schiffer","doi":"10.1098/rsta.2020.0377","DOIUrl":"https://doi.org/10.1098/rsta.2020.0377","url":null,"abstract":"The Born–Oppenheimer approximation, which assumes that the electrons respond instantaneously to the motion of the nuclei, breaks down for a wide range of chemical and biological processes. The rate constants of such nonadiabatic processes can be calculated using analytical theories, and the real-time nonequilibrium dynamics can be described using numerical atomistic simulations. The selection of an approach depends on the desired balance between accuracy and efficiency. The computational expense of generating potential energy surfaces on-the-fly often favours the use of approximate, robust and efficient methods such as trajectory surface hopping for large, complex systems. The development of formally exact non-Born–Oppenheimer methods and the exploration of well-defined approximations to such methods are critical for providing benchmarks and preparing for the next generation of faster computers. Thus, the parallel development of rigorous but computationally expensive methods and more approximate but computationally efficient methods is optimal. This Perspective briefly summarizes the available theoretical and computational non-Born–Oppenheimer methods and presents examples illustrating how analytical theories and nonadiabatic dynamics simulations can elucidate the fundamental principles of chemical and biological processes. These examples also highlight how theoretical calculations are able to guide the interpretation of experimental data and provide experimentally testable predictions for nonadiabatic processes. This article is part of the theme issue ‘Chemistry without the Born–Oppenheimer approximation’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86522516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Quantum flux densities for electronic–nuclear motion: exact versus Born–Oppenheimer dynamics 电子-核运动的量子通量密度:精确与玻恩-奥本海默动力学

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-28 DOI: 10.1098/rsta.2020.0385

T. Schaupp, V. Engel

引用次数: 3

Mixed-quantum-classical or fully-quantized dynamics? A unified code to compare methods 混合量子经典动力学还是全量子化动力学?一个统一的代码来比较方法

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-28 DOI: 10.1098/rsta.2020.0386

J. Coonjobeeharry, K. E. Spinlove, C. Sanz Sanz, M. Sapunar, N. Došlić, G. Worth

引用次数: 7

Quantum dynamics with curvilinear coordinates: models and kinetic energy operator 曲线坐标下的量子动力学:模型和动能算子

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-28 DOI: 10.1098/rsta.2020.0388

Emanuele Marsili, F. Agostini, André Nauts, D. Lauvergnat

{"title":"Quantum dynamics with curvilinear coordinates: models and kinetic energy operator","authors":"Emanuele Marsili, F. Agostini, André Nauts, D. Lauvergnat","doi":"10.1098/rsta.2020.0388","DOIUrl":"https://doi.org/10.1098/rsta.2020.0388","url":null,"abstract":"In order to simplify the numerical solution of the time-dependent or time-independent Schrödinger equations associated with atomic and molecular motions, the use of well-adapted coordinates is essential. Usually, this set of curvilinear coordinates leads to a Hamiltonian operator that is as separable as possible. Although their corresponding kinetic energy operator (KEO) expressions can be derived analytically for small systems or special kinds of coordinates, a numerical and exact approach allows one to compute them in terms of sophisticated curvilinear coordinates. Furthermore, the numerical approach enables one to easily define reduced-dimensionality or constrained models. We present here a recent implementation of this numerical approach that allows nested coordinate transformations, therefore leading to great flexibility in the definition of the curvilinear coordinates. Furthermore, this implementation has no limitations in terms of numbers of atoms or coordinate transformations. The quantum dynamics of the cis–trans photoisomerization of part of the retinal chromophore illustrates the construction of the coordinates and KEO part of a three-dimensional model. This article is part of the theme issue ‘Chemistry without the Born–Oppenheimer approximation’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83587728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Non-Born–Oppenheimer effects in molecular photochemistry: an experimental perspective 分子光化学中的非玻恩-奥本海默效应:实验视角

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-28 DOI: 10.1098/rsta.2020.0376

M. Ashfold, Sang Kyu Kim

引用次数: 5

The moving crude adiabatic alternative to the adiabatic representation in excited state dynamics 激发态动力学中绝热表示的移动粗绝热替代

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-28 DOI: 10.1098/rsta.2020.0379

Rosa Maskri, Loïc Joubert-Doriol

{"title":"The moving crude adiabatic alternative to the adiabatic representation in excited state dynamics","authors":"Rosa Maskri, Loïc Joubert-Doriol","doi":"10.1098/rsta.2020.0379","DOIUrl":"https://doi.org/10.1098/rsta.2020.0379","url":null,"abstract":"The choice of the electronic representation in on-the-fly quantum dynamics is crucial. The adiabatic representation is appealing since adiabatic states are readily available from quantum chemistry packages. The nuclear wavepackets are then expanded in a basis of Gaussian functions, which follow trajectories to explore the potential energy surfaces and approximate the potential using a local expansion of the adiabatic quantities. Nevertheless, the adiabatic representation is plagued with severe limitations when conical intersections are involved: the diagonal Born–Oppenheimer corrections (DBOCs) are non-integrable, and the geometric phase effect on the nuclear wavepackets cannot be accounted for unless a model is available. To circumvent these difficulties, the moving crude adiabatic (MCA) representation was proposed and successfully tested in low energy dynamics where the wavepacket skirts the conical intersection. We assess the MCA representation in the case of non-adiabatic transitions through conical intersections. First, we show that using a Gaussian basis in the adiabatic representation indeed exhibits the aforementioned difficulties with a special emphasis on the possibility to regularize the DBOC terms. Then, we show that MCA is indeed able to properly model non-adiabatic transitions. Tests are done on linear vibronic coupling models for the bis(methylene) adamantyl cation and the butatriene cation. This article is part of the theme issue ‘Chemistry without the Born–Oppenheimer approximation’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80595131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

On stable exponential cosmological solutions with two factor spaces in (1+ m + 2)-dimensional Einstein–Gauss–Bonnet model with Λ-term 具有Λ-term的(1+ m + 2)维Einstein-Gauss-Bonnet模型中具有两因子空间的稳定指数宇宙学解

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-14 DOI: 10.1098/rsta.2021.0177

V. Ivashchuk, A. A. Kobtsev

引用次数: 0

Cosmological milestones, conformal frameworks and quiescent cosmology 宇宙学里程碑，共形框架和静态宇宙学

Philosophical Transactions of the Royal Society A Pub Date : 2022-03-14 DOI: 10.1098/rsta.2021.0172

S. Scott, Philip Threlfall

{"title":"Cosmological milestones, conformal frameworks and quiescent cosmology","authors":"S. Scott, Philip Threlfall","doi":"10.1098/rsta.2021.0172","DOIUrl":"https://doi.org/10.1098/rsta.2021.0172","url":null,"abstract":"To understand the nature of the birth of our Universe and its eventual demise is a driving force in theoretical physics and astronomy and, indeed, for humanity. A zoo of definitions has appeared in the literature to catalogue different types of cosmological milestones such as ‘Big Bangs’, ‘Big Crunches’, ‘Big Rips’, ‘Sudden Singularities’, ‘Bounces’ and ‘Turnarounds’. Quiescent cosmology is the notion that the Universe commenced in a Big Bang that was highly regular and smooth, and evolved away from this initial isotropy and homogeneity due to gravitational attraction. The quiescent cosmology concept meshes well with Penrose’s ideas regarding gravitational entropy and the clumping of matter, and the associated Weyl Curvature Hypothesis. Conformal frameworks, such as the Isotropic Past Singularity (IPS), have been devised to encapsulate initial and final states for the Universe which are in accordance with these programmes. These geometric definitions are independent of models, coordinates and the equation of state of the source of the gravitational field. Much of the research on cosmological milestones has been focussed on the FRW solutions, many of which possess initial singularities which are isotropic Big Bangs. We analyse here the relationship between cosmological milestones and conformal frameworks for these solutions. We establish the general properties of FRW models which admit these conformal frameworks, including whether they satisfy various energy conditions, and are therefore physically reasonable. These results inform future development of the quiescent cosmology program. This article is part of the theme issue ‘The future of mathematical cosmology, Volume 1’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89868437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Scientific advice for policymakers on climate change: the role of evidence synthesis 为气候变化政策制定者提供的科学建议:证据综合的作用

Philosophical Transactions of the Royal Society A Pub Date : 2022-02-28 DOI: 10.1098/rsta.2021.0147

E. Surkovic, David Vigar

引用次数: 1

Distributed renewable energy systems for resilient and sustainable development of remote and vulnerable communities 分布式可再生能源系统，促进偏远和脆弱社区的弹性和可持续发展

Philosophical Transactions of the Royal Society A Pub Date : 2022-02-28 DOI: 10.1098/rsta.2021.0143

Tanvir Ahmad, Saddam Ali, Abdul Basit

{"title":"Distributed renewable energy systems for resilient and sustainable development of remote and vulnerable communities","authors":"Tanvir Ahmad, Saddam Ali, Abdul Basit","doi":"10.1098/rsta.2021.0143","DOIUrl":"https://doi.org/10.1098/rsta.2021.0143","url":null,"abstract":"More than 940 million people (13% of the world population) do not have any access to electricity. Most of these people live in rural and remote areas, where the lack of electricity access is significantly damaging the quality of life, economic development and the environment. Distributed energy systems (DESs) (based on clean energy technologies) for energy access offer a potentially important strategy for pursuing environment-friendly sustainable development and poverty alleviation; especially in rural and remote communities. DESs are also helpful in reducing deforestation and greenhouse gas (GHG) emissions as the fossil fuel-based energy production is among the largest contributors to GHG emissions. This paper presents the importance of energy access through DESs for resilient and sustainable development using two projects case studies from Pakistan. The first project case study is based on the Afghan refugee villages, where, currently, there is no electricity access. A baseline survey was conducted to assess the socio-economic conditions and energy demand of the refugees. This assessment is then used to devise clean energy solutions as per the local context. This project aims to improve the quality of life of the refugees by providing energy access. In the second case study, electricity access was provided to the local communities a few years ago. Analyses of primary data collected in this case study show that DES integrated with socio-economic and cultural systems can bring a significantly positive impact on the local communities, advancing all the sustainability development goals. This work concludes that DES can be significantly generative, if effectively integrated into socio-economic processes. This article is part of the theme issue ‘Developing resilient energy systems’.","PeriodicalId":20020,"journal":{"name":"Philosophical Transactions of the Royal Society A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75670495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2