scholarly journals Mechanism of photocatalytic water oxidation on small TiO2 nanoparticles

2017 ◽  
Vol 8 (3) ◽  
pp. 2179-2183 ◽  
Author(s):  
Mikko Muuronen ◽  
Shane M. Parker ◽  
Enrico Berardo ◽  
Alexander Le ◽  
Martijn A. Zwijnenburg ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Proton Transfer ◽  
Molecular Dynamics Simulations ◽  
Tio2 Nanoparticles ◽  
Hydroxyl Radicals ◽  
Water Oxidation ◽  
Nonadiabatic Molecular Dynamics ◽  
Dynamics Simulations ◽  
Electron Proton Transfer

Nonadiabatic molecular dynamics simulations suggest an excited state electron proton transfer mechanism and explain the observation of mobile hydroxyl radicals.

Photorelaxation of imidazole and adenine via electron-driven proton transfer along H2O wires

2016 ◽  
Vol 195 ◽  
pp. 237-251 ◽  
Author(s):  
Rafał Szabla ◽  
Robert W. Góra ◽  
Mikołaj Janicki ◽  
Jiří Šponer
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Potential Energy ◽  
Proton Transfer ◽  
Potential Energy Surface ◽  
Molecular Dynamics Simulations ◽  
Gas Phase ◽  
Energy Surface ◽  
Water Molecules ◽  
Dynamics Simulations

Photochemically created πσ* states were classified among the most prominent factors determining the ultrafast radiationless deactivation and photostability of many biomolecular building blocks. In the past two decades, the gas phase photochemistry of πσ* excitations was extensively investigated and was attributed to N–H and O–H bond fission processes. However, complete understanding of the complex photorelaxation pathways of πσ* states in the aqueous environment was very challenging, owing to the direct participation of solvent molecules in the excited-state deactivation. Here, we present non-adiabatic molecular dynamics simulations and potential energy surface calculations of the photoexcited imidazole–(H2O)5 cluster using the algebraic diagrammatic construction method to the second-order [ADC(2)]. We show that electron driven proton transfer (EDPT) along a wire of at least two water molecules may lead to the formation of a πσ*/S0 state crossing, similarly to what we suggested for 2-aminooxazole. We expand on our previous findings by direct comparison of the imidazole–(H2O)5 cluster to non-adiabatic molecular dynamics simulations of imidazole in the gas phase, which reveal that the presence of water molecules extends the overall excited-state lifetime of the chromophore. To embed the results in a biological context, we provide calculations of potential energy surface cuts for the analogous photorelaxation mechanism present in adenine, which contains an imidazole ring in its structure.

Ultrafast excited-state dynamics of isocytosine

2016 ◽  
Vol 18 (30) ◽  
pp. 20208-20218 ◽  
Author(s):  
Rafał Szabla ◽  
Robert W. Góra ◽  
Jiří Šponer
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Molecular Dynamics Simulations ◽  
Excited State Dynamics ◽  
Nonadiabatic Molecular Dynamics ◽  
Dynamics Simulations

Nonadiabatic molecular dynamics simulations elucidate the ultrafast photodeactivation mechanisms of alternative nucleobase isocytosine.

Mechanistic analysis of light-driven overcrowded alkene-based molecular motors by multiscale molecular simulations

2021 ◽  
Vol 23 (14) ◽  
pp. 8525-8540
Author(s):  
Mudong Feng ◽  
Michael K. Gilson
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Molecular Dynamics Simulations ◽  
Ground State ◽  
Molecular Motors ◽  
Motor Performance ◽  
Molecular Simulations ◽  
Mechanistic Analysis ◽  
Dynamics Simulations ◽  
Shed Light

Ground-state and excited-state molecular dynamics simulations shed light on the rotation mechanism of small, light-driven molecular motors and predict motor performance. How fast can they rotate; how much torque and power can they generate?

scholarly journals Cavity hydration dynamics in cytochrome c oxidase and functional implications

2017 ◽  
Vol 114 (42) ◽  
pp. E8830-E8836 ◽  
Author(s):  
Chang Yun Son ◽  
Arun Yethiraj ◽  
Qiang Cui
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Proton Transfer ◽  
Molecular Dynamics Simulations ◽  
Transmembrane Protein ◽  
Wetting Transition ◽  
Protonation State ◽  
Hydration Level ◽  
Level Change ◽  
Dynamics Simulations

Cytochrome c oxidase (CcO) is a transmembrane protein that uses the free energy of O2 reduction to generate the proton concentration gradient across the membrane. The regulation of competitive proton transfer pathways has been established to be essential to the vectorial transport efficiency of CcO, yet the underlying mechanism at the molecular level remains lacking. Recent studies have highlighted the potential importance of hydration-level change in an internal cavity that connects the proton entrance channel, the site of O2 reduction, and the putative proton exit route. In this work, we use atomistic molecular dynamics simulations to investigate the energetics and timescales associated with the volume fluctuation and hydration-level change in this central cavity. Extensive unrestrained molecular dynamics simulations (accumulatively ∼4 μs) and free energy computations for different chemical states of CcO support a model in which the volume and hydration level of the cavity are regulated by the protonation state of a propionate group of heme a3 and, to a lesser degree, the redox state of heme a and protonation state of Glu286. Markov-state model analysis of ∼2-μs trajectories suggests that hydration-level change occurs on the timescale of 100–200 ns before the proton-loading site is protonated. The computed energetic and kinetic features for the cavity wetting transition suggest that reversible hydration-level change of the cavity can indeed be a key factor that regulates the branching of proton transfer events and therefore contributes to the vectorial efficiency of proton transport.

Ab Initio Molecular Dynamics Simulations of an Excited State of X-(H2O)3(X = Cl, I) Complex

2005 ◽  
Vol 109 (42) ◽  
pp. 9419-9423 ◽  
Author(s):  
M. Kołaski ◽  
Han Myoung Lee ◽  
Chaeho Pak ◽  
M. Dupuis ◽  
Kwang S. Kim
Keyword(s):  
Molecular Dynamics ◽  
Excited State ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Ab Initio Molecular Dynamics ◽  
Dynamics Simulations
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