scholarly journals Local Phonon Environment as a Design Element for Long-lived Excitonic Coherence: Dithia-anthracenophane Revisited

2022 ◽  
Author(s):  
Govind Sidhardh ◽  
Adithi Ajith ◽  
Ebin Sebastian ◽  
Mahesh Hariharan ◽  
Anil Shaji
Keyword(s):  
Quantum Coherence ◽  
Equations Of Motion ◽  
Design Element ◽  
Light Harvesting Complexes ◽  
Actual Structure ◽  
Exciton Dynamics ◽  
Design Elements ◽  
Molecular Systems ◽  
Reorganisation Energy

Excitonic energy transfer in light harvesting complexes, the primary process of photosynthesis, operates with near-unity efficiency. Experimental and theoretical studies suggest that quantum mechanical wave-like motion of excitons in the pigment-protein complex may be responsible for this quantum efficiency. Observed coherent exciton dynamics can be modelled completely only if we consider the interaction of the exciton with its complex environment. While it is known that the relative orientation of the chromophore units and reorganisation energy are important design elements, the role of a structured phonon environment is often not considered. The purpose of this study is to investigate the role of a structured immediate phonon environment in determining the exciton dynamics and the possibility of using it as an optimal design element. Through the case study of dithia-anthracenophane, a bichromophore using the Hierarchical Equations Of Motion formalism, we show that the experimentally observed coherent exciton dynamics can be reproduced only by considering the actual structure of the phonon environment. While the slow dephasing of quantum coherence in dithia-anthracenophane can be attributed to strong vibronic coupling to high-frequency modes, vibronic quenching is the source of long oscillation periods in population transfer. This study sheds light on the crucial role of the structure of the immediate phonon environment in determining the exciton dynamics. We conclude by proposing some design principles for sustaining long-lived coherence in molecular systems.

scholarly journals Parametric Mapping of Quantum Regime in Fenna–Matthews–Olson Light-Harvesting Complexes: A Synthetic Review of Models, Methods and Approaches

2020 ◽  
Vol 10 (18) ◽  
pp. 6474
Author(s):  
Bruno González-Soria ◽  
Francisco Delgado ◽  
Alan Anaya-Morales
Keyword(s):  
Quantum Coherence ◽  
Open Systems ◽  
Equations Of Motion ◽  
Green Sulfur Bacteria ◽  
Photosynthetic Performance ◽  
Physical Parameters ◽  
Main Process ◽  
Light Harvesting Complexes ◽  
Quantum Regime ◽  
Markovian Approach

Developments in ultrafast-spectroscopy techniques have revealed notably long-lived quantum coherence between electronic states in Fenna–Matthews–Olson complex bacteriochlorophylls, a group of molecules setting a nanoscale structure responsible of the coherent energy transfer in the photosynthetic process of green sulfur bacteria. Despite the experimental advances, such a task should normally be complemented with physical computer simulations to understand its complexity. Several methods have been explored to model this quantum phenomenon, mainly using the quantum open systems theory as a first approach. The traditional methods used in this approach do not take into account the memory effects of the surroundings, which is commonly approximated as a phonon bath on thermal equilibrium. To surpass such an approximation, this article applies the Hierarchical Equations of Motion method, a non-markovian approach also used to analyze the dynamic of such a complex, for the modeling of the system evolution. We perform a parametric analysis about some physical features in the quantum regime involved during the quantum excitation process in order to get a comprehension about its non-trivial dependence on operation parameters. Thus, the analysis is conducted in terms of some relevant physical parameters in the system to track the complex global behavior in aspects as coherence, entanglement, decoherence times, transference times, and efficiency of the main process of energy capturing. As a complementary analysis from the derived outcomes, we compare those features for two different species as a suggestive possible roadmap to track genetic differences in the photosynthetic performance of the complex through its biological nature.

scholarly journals Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer

2017 ◽  
Vol 114 (32) ◽  
pp. 8493-8498 ◽  
Author(s):  
Hong-Guang Duan ◽  
Valentyn I. Prokhorenko ◽  
Richard J. Cogdell ◽  
Khuram Ashraf ◽  
Amy L. Stevens ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Quantum Coherence ◽  
Light Harvesting ◽  
Electronic Excitation Energy ◽  
Light Harvesting Complexes ◽  
Ultrafast Optical ◽  
Ultrafast Optical Spectroscopy ◽  
Biomolecular Complexes ◽  
Orthodox View

During the first steps of photosynthesis, the energy of impinging solar photons is transformed into electronic excitation energy of the light-harvesting biomolecular complexes. The subsequent energy transfer to the reaction center is commonly rationalized in terms of excitons moving on a grid of biomolecular chromophores on typical timescales <100 fs. Today’s understanding of the energy transfer includes the fact that the excitons are delocalized over a few neighboring sites, but the role of quantum coherence is considered as irrelevant for the transfer dynamics because it typically decays within a few tens of femtoseconds. This orthodox picture of incoherent energy transfer between clusters of a few pigments sharing delocalized excitons has been challenged by ultrafast optical spectroscopy experiments with the Fenna–Matthews–Olson protein, in which interference oscillatory signals up to 1.5 ps were reported and interpreted as direct evidence of exceptionally long-lived electronic quantum coherence. Here, we show that the optical 2D photon echo spectra of this complex at ambient temperature in aqueous solution do not provide evidence of any long-lived electronic quantum coherence, but confirm the orthodox view of rapidly decaying electronic quantum coherence on a timescale of 60 fs. Our results can be considered as generic and give no hint that electronic quantum coherence plays any biofunctional role in real photoactive biomolecular complexes. Because in this structurally well-defined protein the distances between bacteriochlorophylls are comparable to those of other light-harvesting complexes, we anticipate that this finding is general and directly applies to even larger photoactive biomolecular complexes.

THE ROLE OF INTERIOR DESIGN ELEMENTS IN ACHIEVING THE EMPLOYEES PHYSIOLOGICAL NEEDS IN OFFICE BUILDINGS

2019 ◽  
Vol 14 (51) ◽  
pp. 764-779
Author(s):  
Hassan Metwally ◽  
Ahmed El Sayed ◽  
Hanan Ashraf Kamal El- Ashmawy
Keyword(s):  
Interior Design ◽  
Office Buildings ◽  
Design Elements

Consumers Complain More Fiercely Through Small-Screen Devices: The Role of Spatial Crowding Perception

2020 ◽  
Vol 23 (3) ◽  
pp. 353-367
Author(s):  
Yuanyuan Zhou ◽  
Bin Tian ◽  
Tingting Mo ◽  
Zhuoying Fei
Keyword(s):  
Secondary Data ◽  
Underlying Mechanism ◽  
Screen Size ◽  
Design Elements ◽  
Perception Theory ◽  
Fourth Experiment ◽  
Complaint Behavior ◽  
The Relationship ◽  
Small Screen

Previous research has mainly focused on the determinants of consumers’ complaint channel choices. Little attention has been paid to the behavioral consequences of different complaint channels, particularly different complaint devices. Drawing on spatial crowding perception theory, this study finds that in an online complaint context, consumers’ complaint intensity is shaped by complaint devices that differ in screen size. Crowding perception produced by visually restrictive tension mediates the relationship between the screen size of the complaint device and the complaint intensity. The results of secondary data confirm that consumers’ complaint intensity is higher while complaining through a small-screen device (as opposed to a large-screen one). Three scenario-based experiments are conducted to examine the role of perceived spatial crowding in producing a more intense complaint behavior when complaints are submitted through smaller screen devices (as opposed to larger screen devices). The fourth experiment reveals that crowding perception can be lessened by adjusting certain design elements of the interface, ultimately mitigating the intensity of the complaint submitted through a small-screen device. Our research identifies the specific causality and underlying mechanism of the influence of device type on consumers’ postconsumption behavior, thus contributing to clarify some ambiguities in the literature.

Investigation of Train Dynamics in Passing Through Curves Using a Full Model

Joint Rail ◽  
2004 ◽  
Author(s):  
Mohammad Durali ◽  
Mohammad Mehdi Jalili Bahabadi
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Full Model ◽  
Bogie Frame ◽  
Nonlinear Characteristics ◽  
Train Derailment ◽  
Train Dynamics

In this article a train model is developed for studying train derailment in passing through bends. The model is three dimensional, nonlinear, and considers 43 degrees of freedom for each wagon. All nonlinear characteristics of suspension elements as well as flexibilities of wagon body and bogie frame, and the effect of coupler forces are included in the model. The equations of motion for the train are solved numerically for different train conditions. A neural network was constructed as an element in solution loop for determination of wheel-rail contact geometry. Derailment factor was calculated for each case. The results are presented and show the major role of coupler forces on possible train derailment.

It’s All Fun and Games: The Role of Gamification in E-banking

2021 ◽  
Vol 65 (1) ◽  
pp. 1297-1301
Author(s):  
Meenu Sethu ◽  
Dan Nathan-Roberts
Keyword(s):  
Financial Institutions ◽  
Game Design ◽  
Customer Engagement ◽  
The Internet ◽  
Design Elements ◽  
Online Transactions ◽  
Game Mechanics ◽  
Factors Influencing ◽  
Novel Approach

Traditional banks and financial institutions have witnessed a profound transformation to electronic banking with the rise of the internet over the last two decades. However, most digital banking customers do not feel that the activity of managing their money and making online transactions is exciting or enjoyable. The gamification of e-banking systems is a novel approach for promoting customer engagement that is gaining popularity. This work reviews the factors influencing the adoption of e-banking and how gamification can be used to improve customer engagement, loyalty, and financial wellbeing. An exploration of the most extensively used game design elements in gamified e-banking applications suggests that the use of certain game mechanics and characteristics can be effective in creating enjoyable banking experiences. Based on this research, a set of guidelines is provided for designers and practitioners for introducing game principles in e-banking applications.

JAHN-TELLER EFFECT OF MOLECULAR COMPLEXES IN LIQUID SOLUTIONS

1994 ◽  
Vol 08 (21n22) ◽  
pp. 1319-1334 ◽  
Author(s):  
J.W. HALLEY ◽  
X.R. WANG
Keyword(s):  
Quantum Coherence ◽  
Berry Phase ◽  
Molecular Complexes ◽  
Liquid Solution ◽  
Teller Effect ◽  
Liquid Systems ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Molecular Dynamics Methods

We review recent work clarifying the sense in which the Jahn-Teller effect can exist in a molecular complex in liquid solution. We review the molecular dynamics methods for modeling such liquid systems using the cupric ion in aqueous solution as an example. We review the experimental evidence for the Jahn-Teller effect in liquids, emphasizing the importance of taking the time scale of the measurement into account. Finally we discuss the role of quantum coherence and the Berry phase in the Jahn-Teller effect.

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