Controlling Photorelaxation in Uracil with Shaped Laser Pulses: A Theoretical Assessment

Keefer, Daniel; Thallmair, Sebastian; Matsika, Spiridoula; Vivie‐Riedle, Regina de

doi:10.1021/jacs.6b12033

Cited by 40 publications

(99 citation statements)

References 43 publications

(57 reference statements)

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“…Larger fluctuations between the extreme cases can happen within 300 fs. This means that if the control mechanism happens on the low fs timescale, as it is for example the case in the control of excited state processes involving conical intersections, assuming a static environment can be a valid approximation. In the present case, where vibrational initiation of a ground state reaction is performed with ps laser pulses, a fs environmental fluctuation will affect the control mechanism and the complexity of the control task.…”

Section: Resultsmentioning

confidence: 99%

Theoretical Quantum Control of Fluctuating Molecular Energy Levels in Complex Chemical Environments

Keefer

Vivie‐Riedle

2019

Adv Quantum Tech

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In the present study, quantum control simulations are performed to explore the theoretical and practical limits of controlling applied synthetic chemistry in solution. To this extent a reactive model coordinate is used which captures the essential features of an atomistic and dynamic solvent environment during a picosecond control scenario. The time-resolved influence of a molecular environment is revealed to fluctuate on a time-scale of few hundred femtoseconds. Laser pulse optimizations are performed for different control scenarios, giving general experimental guidelines on how to find a reasonable tradeoff between pulse complexity and population yield. Few-cycle flexible terahertz pulses are found to be capable of handling the complexities which are introduced by a fluctuating environment to the quantum properties of the molecular system. Besides the practical limitations in pulse generation and shaping, there seem to be no theoretical limits to controlling the investigated process with its environmental fluctuations. As the chosen model system involves a methyl group transfer and carbon-carbon formation, it stands representative for other commonly performed synthetic schemes in modern organic and pharmaceutical chemistry.

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Section: Resultsmentioning

confidence: 99%

Theoretical Quantum Control of Fluctuating Molecular Energy Levels in Complex Chemical Environments

Keefer

Vivie‐Riedle

2019

Adv Quantum Tech

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“…The chosen active space and the MRCI expansions have been previously benchmarked and used in many previous studies of uracil. [81][82][83] Na(NH 3 ) n , n = 1. . .3.…”

Section: Computational Detailsmentioning

confidence: 99%

Calculations of non-adiabatic couplings within equation-of-motion coupled-cluster framework: Theory, implementation, and validation against multi-reference methods

Faraji

Matsika

Krylov

2018

The Journal of Chemical Physics

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We report an implementation of non-adiabatic coupling (NAC) forces within the equation-of-motion coupled-cluster with single and double excitations (EOM-CCSD) framework via the summed-state approach. Using illustrative examples, we compare NAC forces computed with EOM-CCSD and multi-reference (MR) wave functions (for selected cases, we also consider configuration interaction singles). In addition to the magnitude of the NAC vectors, we analyze their direction, which is important for the calculations of the rate of non-adiabatic transitions. Our benchmark set comprises three doublet radical-cations (hexatriene, cyclohexadiene, and uracil), neutral uracil, and sodium-doped ammonia clusters. When the characters of the states agree among different methods, we observe good agreement between the respective NAC vectors, both in the Franck-Condon region and away. In the cases of large discrepancies between the methods, the disagreement can be attributed to the difference in the states' character, which, in some cases, is very sensitive to electron correlation, both within single-reference and multi-reference frameworks. The numeric results confirm that the accuracy of NAC vectors depends critically on the quality of the underlying wave functions. Within their domain of applicability, EOM-CC methods provide a viable alternative to MR approaches.

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“…a conical intersection is visited by an excited state nuclear wavepacket, which is launched in the Franck-Condon region. A number of explicit simulations of the excited state wavepacket dynamics have been published so far [18][19][20][21][22][23][24][25][26][27][28][29][30]. Their results are well summarized in ref.…”

Section: Ultrafast Dynamics Of Nucleobasesmentioning

confidence: 99%

Photochemical pathways in nucleobases measured with an X-ray FEL

Wolf

Gühr

2019

Phil. Trans. R. Soc. A.

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The conversion of light energy into other molecular energetic degrees of freedom is often dominated by ultrafast, non-adiabatic processes. Femtosecond spectroscopy with optical pulses has helped in shaping our understanding of crucial processes in molecular energy-conversion. The advent of new, ultrashort and bright X-ray free electron laser sources opens the possibility to use X-ray-typical element and site sensitivity for ultrafast molecular research. We present two types of spectroscopy, ultrafast Auger and ultrafast X-ray absorption spectroscopy, and discuss their sensitivity to molecular processes. While Auger spectroscopy is able to monitor bond distance changes in the vicinity of an X-ray created core hole, near-edge absorption spectroscopy can deliver high-fidelity information on non-adiabatic transitions involving lone-pair orbitals. We demonstrate these features on the example of the UV-excited nucleobase thymine, investigated at the oxygen K-edge. We find a C–O bond elongation in the Auger data in addition to ππ* / nπ* non-adiabatic transition in X-ray near-edge absorption. We compare the results from both methods and draw a conclusive scenario of non-adiabatic molecular relaxation after UV excitation. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

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Controlling Photorelaxation in Uracil with Shaped Laser Pulses: A Theoretical Assessment

Cited by 40 publications

References 43 publications

Theoretical Quantum Control of Fluctuating Molecular Energy Levels in Complex Chemical Environments

Theoretical Quantum Control of Fluctuating Molecular Energy Levels in Complex Chemical Environments

Calculations of non-adiabatic couplings within equation-of-motion coupled-cluster framework: Theory, implementation, and validation against multi-reference methods

Photochemical pathways in nucleobases measured with an X-ray FEL

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