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Gorbunova IA, Sasin ME, Beltukov YM, Semenov AA, Vasyutinskii OS. Anisotropic relaxation in NADH excited states studied by polarization-modulation pump-probe transient spectroscopy. Phys Chem Chem Phys 2020; 22:18155-18168. [PMID: 32766648 DOI: 10.1039/d0cp02496a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We present the results of experimental and theoretical studies of fast anisotropic relaxation and rotational diffusion in the first electron excited state of biological coenzyme NADH in water-ethanol solutions. The experiments have been carried out by means of a novel polarization-modulation transient method and fluorescence polarization spectroscopy. For interpretation of the experimental results a model of the anisotropic relaxation in terms of scalar and vector properties of transition dipole moments has been developed based on the Born-Oppenheimer approximation. This model allows for the description of fast isotropic and anisotropic excited state relaxation under excitation of molecules by ultrafast laser pulses in transient absorption and upconversion experiments. The results obtained suggest that the dynamics of anisotropic rovibronic relaxation in NADH under excitation with 100 fs pump laser pulses can be characterised by a single vibrational relaxation time τv lying in the range of 2-15 ps and a single rotation diffusion time τr lying in the range of 100-450 ps, both depending on ethanol concentration. The dependence of the times τv and τr on the solution polarity (static permittivity) and viscosity has been determined and analyzed. Limiting values of the term P2(cos θ) describing the rotation of the transition dipole moment in the course of vibrational relaxation have been determined from experiments as a function of ethanol concentration and analyzed.
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Affiliation(s)
| | - Maxim E Sasin
- Ioffe Institute, Polytekhnicheskaya 26, St. Petersburg, Russia.
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Murillo-Sánchez ML, Zanchet A, Marggi Poullain S, González-Vázquez J, Bañares L. Structural dynamics effects on the electronic predissociation of alkyl iodides. Sci Rep 2020; 10:6700. [PMID: 32317645 PMCID: PMC7174404 DOI: 10.1038/s41598-020-62982-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/23/2020] [Indexed: 11/26/2022] Open
Abstract
The correlation between chemical structure and predissociation dynamics has been evaluated for a series of linear and branched alkyl iodides with increasing structural complexity by means of femtosecond time-resolved velocity map imaging experiments following excitation on the second absorption band (B-band) at around 201 nm. The time-resolved images for the iodine fragment are reported and analyzed in order to extract electronic predissociation lifetimes and the temporal evolution of the anisotropy while the experimental results are supported by ab initio calculations of the potential energy curves as a function of the C-I distance. Remarkable similarities are observed for all molecules consistent with a major predissociation of the initially populated bound Rydberg states 6A″ and 7A' through a crossing with the purely repulsive states 7A″, 8A' and 8A″ leading to a major R + I*(2P1/2) (R = CH3, C2H5, n-C3H7, n-C4H9, i-C3H7 and t-C4H9) dissociation channel. The reported electronic predissociation lifetimes are found to decrease for an increasing size of the linear radical, reflecting the shifts observed in the position of the crossings in the potential energy curves, and very likely a greater non-adiabatic coupling between the initially populated Rydberg states and the repulsive states leading to dissociation induced by other coordinates associated to key vibrational normal modes. The loss of anisotropy is fully accounted for by the parent molecular rotation during predissociation and the rotational temperature of the parent molecule in the molecular beam is reasonably derived.
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Affiliation(s)
- Marta L Murillo-Sánchez
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Alexandre Zanchet
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37003, Salamanca, Spain
- Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas, Serrano 123, 28006, Madrid, Spain
| | - Sonia Marggi Poullain
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
- Department of Chemistry, University of California, Berkeley, California, 94720, United States
| | - Jesús González-Vázquez
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Cantoblanco, 28049, Madrid, Spain.
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Murillo-Sánchez ML, Marggi Poullain S, Loriot V, Corrales ME, Bañares L. Femtosecond predissociation dynamics of ethyl iodide in the B-band. Phys Chem Chem Phys 2019; 21:15695-15704. [PMID: 31271396 DOI: 10.1039/c9cp02992c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond time-resolved velocity map ion imaging experiments are reported on the second absorption band (B-band) of ethyl iodide at 201.19 and 200.08 nm, corresponding to the 000 and 1810 transitions, i.e., the origin of the band and the first most intense vibronic state assigned to one quantum of excitation in the methyl torsion mode. Electronic predissociation lifetimes and the temporal evolution of the anisotropy have been determined by time-resolved resonance-enhanced multiphoton ionization of iodine and ethyl fragment images. A shorter lifetime measured at the origin of the band in comparison with methyl iodide indicates that predissociation in ethyl iodide is more favorable due to a stronger coupling between the initial Rydberg state and the valence repulsive state correlating with the dissociation fragments. Moreover, vibrational activity in the methyl torsion in the Rydberg state seems to enhance the probability of transfer of population to the valence repulsive state leading to a faster dissociation. The perpendicular character of the transition at early times and the loss of anisotropy as a function of time have been determined from the time-resolved angular distributions of the iodine and ethyl ion images. The initial anisotropy value is consistent with a purely perpendicular transition compatible with the excitation of the [6A'', 7A'] states with a minor parallel component to the C-I bond. The loss of initial anisotropy over time highlights the parent molecular rotation during predissociation and is compatible with a rotational temperature of the parent molecule of 100 K.
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Affiliation(s)
- Marta L Murillo-Sánchez
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Sonia Marggi Poullain
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Vincent Loriot
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumiére Matiére, F-69622, Villeurbanne, France
| | - Maria E Corrales
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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Serrano-Jiménez A, Bañares L, García-Vela A. Weak-field coherent control of photodissociation in polyatomic molecules. Phys Chem Chem Phys 2019; 21:7885-7893. [PMID: 30916089 DOI: 10.1039/c9cp01214a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A coherent control scheme is suggested to modify the output of photodissociation in a polyatomic system. The performance of the scheme is illustrated by applying it to the ultrafast photodissociation of CH3I in the A-band. The control scheme uses a pump laser weak field that combines two pulses of a few femtoseconds delayed in time. By varying the time delay between the pulses, the shape of the laser field spectral profile is modulated, which causes a change in the initial relative populations excited by the pump laser to the different electronic states involved in the photodissociation. Such a change in the relative populations produces different photodissociation outputs, which is the basis of the control achieved. The degree of control obtained over different photodissociation observables, like the branching ratio between the two dissociation channels of CH3I yielding I(2P3/2) and I*(2P1/2) and the fragment angular distributions associated with each channel, is investigated. These magnitudes are found to oscillate strongly with the time delay, with the branching ratio changing by factors between two and three. Substantial variations of the angular distributions also indicate that the scheme provides a high degree of control. Experimental application of the scheme to general polyatomic photodissociation processes should be straightforward.
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Affiliation(s)
- A Serrano-Jiménez
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
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Baumann A, Rompotis D, Schepp O, Wieland M, Drescher M. Time-Resolved Dissociation Dynamics of Iodomethane Resulting from Rydberg and Valence Excitation. J Phys Chem A 2018; 122:4779-4784. [DOI: 10.1021/acs.jpca.8b01248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arne Baumann
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
| | | | - Oliver Schepp
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
| | - Marek Wieland
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
- Center for Free-Electron Laser Science—CFEL, Hamburg 22607, Germany
| | - Markus Drescher
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
- Center for Free-Electron Laser Science—CFEL, Hamburg 22607, Germany
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Corrales ME, de Nalda R, Bañares L. Strong laser field control of fragment spatial distributions from a photodissociation reaction. Nat Commun 2017; 8:1345. [PMID: 29116091 PMCID: PMC5677097 DOI: 10.1038/s41467-017-01139-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 08/22/2017] [Indexed: 11/10/2022] Open
Abstract
The notion that strong laser light can intervene and modify the dynamical processes of matter has been demonstrated and exploited both in gas and condensed phases. The central objective of laser control schemes has been the modification of branching ratios in chemical processes, under the philosophy that conveniently tailored light can steer the dynamics of a chemical mechanism towards desired targets. Less explored is the role that strong laser control can play on chemical stereodynamics, i.e. the angular distribution of the products of a chemical reaction in space. This work demonstrates for the case of methyl iodide that when a molecular bond breaking process takes place in the presence of an intense infrared laser field, its stereodynamics is profoundly affected, and that the intensity of this laser field can be used as an external knob to control it.
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Affiliation(s)
- María E Corrales
- Departamento de Química Física (Unidad Asociada de I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Rebeca de Nalda
- Instituto de Química Física Rocasolano, CSIC, C/ Serrano 119, 28006, Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física (Unidad Asociada de I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
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