Biologically inspired molecular machines driven by light. Optimal control of a unidirectional rotor

Pérez‐Hernández, Guillermo; Pelzer, Adam; González, Leticia; Seideman, Tamar

doi:10.1088/1367-2630/12/7/075007

Cited by 23 publications

(24 citation statements)

References 71 publications

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“…Thus, the structural changes in 100 fs are not as extensive as required for the final formation of I t *, and the sub picosecond dephasing of the impulsively excited modes precedes the major structural change associated with the cis to trans isomerisation. Interestingly the observation of coherences decaying on the hundreds of femtoseconds time scale raises the possibility of coherent control over motor function, provided that the mode excited is also coupled to the reaction coordinate. Resonant Femtosecond Stimulated Raman Spectroscopy (FSRS) measurements along with excited‐state simulations will enumerate directly the significance of coupled vibrational modes in driving efficient photoisomerisation; such experiments are planned.…”

Section: Discussionmentioning

confidence: 99%

Ultrafast Excited State Dynamics in a First Generation Photomolecular Motor

et al. 2020

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Efficient photomolecular motors will be critical elements in the design and development of molecular machines. Optimisation of the quantum yield for photoisomerisation requires a detailed understanding of molecular dynamics in the excited electronic state. Here we probe the primary photophysical processes in the archetypal first generation photomolecular motor, with sub‐50 fs time resolved fluorescence spectroscopy. A bimodal relaxation is observed with a 100 fs relaxation of the Franck‐Condon state to populate a red‐shifted state with a reduced transition moment, which then undergoes multi‐exponential decay on a picosecond timescale. Oscillations due to the excitation of vibrational coherences in the S1 state are seen to survive the ultrafast structural relaxation. The picosecond relaxation reveals a strong solvent friction effect which is thus ascribed to torsion about the C−C axle. This behaviour is contrasted with second generation photomolecular motors; the principal differences are explained by the existence of a barrier on the excited state surface in the case of the first‐generation motors which is absent in the second generation. These results will help to provide a basis for designing more efficient molecular motors in the future.

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Section: Discussionmentioning

confidence: 99%

Ultrafast Excited State Dynamics in a First Generation Photomolecular Motor

et al. 2020

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“…[1][2][3] Fundamental developments have discovered fascinating phenomena and enabled a wealth of applications in the gas phase, [4][5][6][7][8] in solution, 4,[9][10][11] in crystals, 4,12 on surfaces, [4][5][6][13][14][15] and in biosystems. 16 Here we use a molecular model rotor to demonstrate the way from molecular quantum dynamics to explicitly time dependent statistical thermodynamics.…”

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confidence: 99%

From coherent quasi-irreversible quantum dynamics towards the second law of thermodynamics: The model boron rotor B13+

2018

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The planar boron cluster B13+ provides a model to investigate the microscopic origin of the second law of thermodynamics in a small system. It is a molecular rotor with an inner wheel that rotates in an outer bearing. The cyclic reaction path of B13+ passes along thirty equivalent global minimum structures (GMi, i = 1, 2, ..., 30). The GMs are embedded in a cyclic thirty-well potential. They are separated by thirty equivalent transition states with potential barrier Vb. If the boron rotor B13+ is prepared initially in one of the thirty GMs, with energy below Vb, then it tunnels sequentially to its nearest, next-nearest etc. neighbors (520 fs per step) such that all the other GMs get populated. As a consequence, the entropy of occupying the GMs takes about 6 ps to increases from zero to a value close to the maximum value for equi-distribution. Perfect recurrences are practically not observable.

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“…38 Alternatively, sophisticated choices of laser pulse can be employed to create a uni-directionally rotating wavepacket. 39,40 Such methods offer appealing possibilities for fine control of the initial state of a collision system prior to an investigation of its scattering dynamics. In this study, we also consider a third application, parity selective control over the degree of rotational excitation of the wavepacket.…”

Section: B Characterisation Of Laser Induced Rotational Wavepacketsmentioning

confidence: 99%

Reactive scattering dynamics of rotational wavepackets: A case study using the model H+H2 and F+H2 reactions with aligned and anti-aligned H2

Eyles

Leibscher

2013

The Journal of Chemical Physics

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We propose a method to steer the outcome of reactive atom-diatom scattering, using rotational wavepackets excited by strong non-resonant laser pulses. Full close-coupled quantum mechanical scattering calculations of the D+H2 and F+H2 reactions are presented, where the H2 molecule exists as a coherent superposition of rotational states. The nuclear spin selective control over the molecular bond axis alignment afforded by the creation of rotational wavepackets is applied to reactive scattering systems, enabling a nuclear spin selective influence to be exerted over the reactive dynamics. The extension of the conventional eigenstate-to-eigenstate scattering problem to the case in which the initial state is composed of a coherent superposition of rotational states is detailed, and a selection of example calculations are discussed, along with their mechanistic implications. The feasibility of the corresponding experiments is considered, and a suitable simple two pulse laser scheme is shown to strongly differentiate the reactivities of o-H2 and p-H2.

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Biologically inspired molecular machines driven by light. Optimal control of a unidirectional rotor

Cited by 23 publications

References 71 publications

Ultrafast Excited State Dynamics in a First Generation Photomolecular Motor

Ultrafast Excited State Dynamics in a First Generation Photomolecular Motor

From coherent quasi-irreversible quantum dynamics towards the second law of thermodynamics: The model boron rotor B13+

Reactive scattering dynamics of rotational wavepackets: A case study using the model H+H2 and F+H2 reactions with aligned and anti-aligned H2

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