Modeling of light-harvesting in purple bacteria using a time-dependent Hamiltonian approach

2010 ◽  
Vol 248 (2) ◽  
pp. 393-398 ◽  
Author(s):  
Carsten Olbrich ◽  
Jörg Liebers ◽  
Ulrich Kleinekathöfer
Keyword(s):  
Light Harvesting ◽  
Purple Bacteria ◽  
Time Dependent ◽  
Hamiltonian Approach

scholarly journals Fully Quantum Modeling of Exciton Diffusion in Mesoscale Light Harvesting Systems

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3291
Author(s):  
Fulu Zheng ◽  
Lipeng Chen ◽  
Jianbo Gao ◽  
Yang Zhao
Keyword(s):  
Light Harvesting ◽  
Purple Bacteria ◽  
Time Dependent ◽  
Graphic Processing Units ◽  
Exciton Diffusion ◽  
Quantum Mechanical Treatment ◽  
Exciton Transfer ◽  
Harvesting Systems ◽  
Intractable Problem ◽  
Computational Resources

It has long been a challenge to accurately and efficiently simulate exciton–phonon dynamics in mesoscale photosynthetic systems with a fully quantum mechanical treatment due to extensive computational resources required. In this work, we tackle this seemingly intractable problem by combining the Dirac–Frenkel time-dependent variational method with Davydov trial states and implementing the algorithm in graphic processing units. The phonons are treated on the same footing as the exciton. Tested with toy models, which are nanoarrays of the B850 pigments from the light harvesting 2 complexes of purple bacteria, the methodology is adopted to describe exciton diffusion in huge systems containing more than 1600 molecules. The superradiance enhancement factor extracted from the simulations indicates an exciton delocalization over two to three pigments, in agreement with measurements of fluorescence quantum yield and lifetime in B850 systems. With fractal analysis of the exciton dynamics, it is found that exciton transfer in B850 nanoarrays exhibits a superdiffusion component for about 500 fs. Treating the B850 ring as an aggregate and modeling the inter-ring exciton transfer as incoherent hopping, we also apply the method of classical master equations to estimate exciton diffusion properties in one-dimensional (1D) and two-dimensional (2D) B850 nanoarrays using derived analytical expressions of time-dependent excitation probabilities. For both coherent and incoherent propagation, faster energy transfer is uncovered in 2D nanoarrays than 1D chains, owing to availability of more numerous propagating channels in the 2D arrangement.

scholarly journals Hamiltonian Approach to Magnetic Fields with Toroidal Surfaces

1985 ◽  
Vol 40 (10) ◽  
pp. 959-967
Author(s):  
A. Salat
Keyword(s):  
Magnetic Field ◽  
Hamiltonian System ◽  
Magnetic Fields ◽  
Constant Pressure ◽  
Time Dependent ◽  
Hamiltonian Approach ◽  
One Dimensional ◽  
Mhd Equilibrium ◽  
Magnetic Surfaces ◽  
Rotational Transform

The equivalence of magnetic field line equations to a one-dimensional time-dependent Hamiltonian system is used to construct magnetic fields with arbitrary toroidal magnetic surfaces I = const. For this purpose Hamiltonians H which together with their invariants satisfy periodicity constraints have to be known. The choice of H fixes the rotational transform η(I). Arbitrary axisymmetric fields, and nonaxisymmetric fields with constant η(I) are considered in detail.Configurations with coinciding magnetic and current density surfaces are obtained. The approach used is not well suited, however, to satisfying the additional MHD equilibrium condition of constant pressure on magnetic surfaces.

scholarly journals The molecular mechanisms of light adaption in light-harvesting complexes of purple bacteria revealed by a multiscale modeling

2019 ◽  
Vol 10 (42) ◽  
pp. 9650-9662 ◽  
Author(s):  
Felipe Cardoso Ramos ◽  
Michele Nottoli ◽  
Lorenzo Cupellini ◽  
Benedetta Mennucci
Keyword(s):  
Multiscale Modeling ◽  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Purple Bacteria ◽  
Spectral Tuning ◽  
Light Harvesting Complexes

The spectral tuning of LH2 antenna complexes arises from H-bonding, acetyl torsion, and inter-chromophore couplings.

B800–B850 coherence correlates with energy transfer rates in the LH2 complex of photosynthetic purple bacteria

2015 ◽  
Vol 17 (46) ◽  
pp. 30805-30816 ◽  
Author(s):  
Cathal Smyth ◽  
Daniel G. Oblinsky ◽  
Gregory D. Scholes
Keyword(s):  
Energy Transfer ◽  
Quantum Information ◽  
Information Science ◽  
Light Harvesting ◽  
Purple Bacteria ◽  
Quantum Information Science ◽  
Light Harvesting Complex ◽  
Transfer Rates ◽  
Photosynthetic Purple Bacteria

Delocalization of a model light-harvesting complex is investigated using multipartite measures inspired by quantum information science.

Coupling to Charge Transfer States is the Key to Modulate the Optical Bands for Efficient Light Harvesting in Purple Bacteria

2018 ◽  
Vol 9 (23) ◽  
pp. 6892-6899 ◽  
Author(s):  
Lorenzo Cupellini ◽  
Stefano Caprasecca ◽  
Ciro A. Guido ◽  
Frank Müh ◽  
Thomas Renger ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Light Harvesting ◽  
Purple Bacteria
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