1
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G. Arcos C, García-Vela A, Sola IR. Impact of Early Coherences on the Control of Ultrafast Photodissociation Reactions. J Phys Chem Lett 2024; 15:1442-1448. [PMID: 38291810 PMCID: PMC10860130 DOI: 10.1021/acs.jpclett.3c03430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/01/2024]
Abstract
By coherent control, the yield of photodissociation reactions can be maximized, starting in a suitable superposition of vibrational states. In ultrafast processes, the interfering pathways are born from the early vibrational coherences in the ground electronic potential. We interpret their effect from a purely classical picture, in which the correlation between the initial position and momentum helps to synchronize the vibrational dynamics at the Franck-Condon window when the pulse is at its maximum intensity. In the quantum domain, we show that this localization in time and space is mediated by dynamic squeezing of the wave packet.
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Affiliation(s)
- Carlos G. Arcos
- Departamento
de Física Interdisciplinar, Universidad
Nacional de Educación a Distancia, 28232 Las Rozas, Spain
| | - Alberto García-Vela
- Instituto
de Física Fundamental, Consejo Superior
de Investigaciones Científicas, Serrano, 123, 28006 Madrid, Spain
| | - Ignacio R. Sola
- Departamento
de Química Física, Universidad
Complutense de Madrid, 28040 Madrid, Spain
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2
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Jin J, Grellmann M, Asmis KR. Nuclear quantum dynamics on the ground electronic state of neutral silver dimer 107Ag 109Ag probed by femtosecond NeNePo spectroscopy. Phys Chem Chem Phys 2023; 25:24313-24320. [PMID: 37664952 DOI: 10.1039/d3cp02055j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The nuclear quantum dynamics on the ground electronic state of the neutral silver dimer 107Ag109Ag are studied by femtosecond (fs) pump-probe spectroscopy using the 'negative ion - to neutral - to positive ion' (NeNePo) excitation scheme. A vibrational wave packet is prepared on the X1Σ+g state of Ag2via photodetachment of mass-selected, cryogenically cooled Ag2- using a first ultrafast pump laser pulse. The temporal evolution of the wave packet is then probed by an ultrafast probe pulse via resonant multiphoton ionization to Ag2+. Frequency analysis of the fs-NeNePo spectra obtained for a single isotopologue and pump-probe delay times up to 60 ps yields the harmonic (ωe = 192.2 cm-1), quadratic anharmonic (ωexe = 0.637 cm-1) and cubic anharmonic (ωeye = 3 × 10-4 cm-1) constants for the X1Σ+g state of neutral Ag2. The fs-NeNePo spectra obtained at different pump wavelengths provide insight into the excitation mechanism. At a pump wavelength of 510 nm instead of 1010 nm, resonant excitation of a short-lived electronically excited state of the anion followed by autodetachment results in population of higher-energy vibrational levels of the neutral ground state. In contrast, at 1140 nm dynamics with a slightly shorter beating period and different relative phase are observed. The present study demonstrates that isotopologue-specific fs-NeNePo spectroscopy provides accurate vibrational constants of mass-selected neutral clusters in their electronic ground state in the terahertz spectral region, which remains difficult to obtain directly in the frequency domain with any other type of spectroscopy of comparable sensitivity.
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Affiliation(s)
- Jiaye Jin
- Wilhelm-Ostwald-Institut für Physikalische und Theoretisch Chemie, Universität Leipzig, Linnéstr. 2, 04103 Leipzig, Germany.
| | - Max Grellmann
- Wilhelm-Ostwald-Institut für Physikalische und Theoretisch Chemie, Universität Leipzig, Linnéstr. 2, 04103 Leipzig, Germany.
| | - Knut R Asmis
- Wilhelm-Ostwald-Institut für Physikalische und Theoretisch Chemie, Universität Leipzig, Linnéstr. 2, 04103 Leipzig, Germany.
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3
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Kotsina N, Brahms C, Jackson S, Travers JC, Townsend D. Spectroscopic application of few-femtosecond deep-ultraviolet laser pulses from resonant dispersive wave emission in a hollow capillary fibre. Chem Sci 2022; 13:9586-9594. [PMID: 36091901 PMCID: PMC9400683 DOI: 10.1039/d2sc02185d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 07/25/2022] [Indexed: 11/21/2022] Open
Abstract
We exploit the phenomenon of resonant dispersive wave (RDW) emission in gas-filled hollow capillary fibres (HCFs) to realize time-resolved photoelectron imaging (TRPEI) measurements with an extremely short temporal resolution. By integrating the output end of an HCF directly into a vacuum chamber assembly we demonstrate two-colour deep ultraviolet (DUV)-infrared instrument response functions of just 10 and 11 fs at central pump wavelengths of 250 and 280 nm, respectively. This result represents an advance in the current state of the art for ultrafast photoelectron spectroscopy. We also present an initial TRPEI measurement investigating the excited-state photochemical dynamics operating in the N-methylpyrrolidine molecule. Given the substantial interest in generating extremely short and highly tuneable DUV pulses for many advanced spectroscopic applications, we anticipate our first demonstration will stimulate wider uptake of the novel RDW-based approach for studying ultrafast photochemistry – particularly given the relatively compact and straightforward nature of the HCF setup. We exploit the phenomenon of resonant dispersive wave emission in gas-filled hollow capillary fibres to realize time-resolved photoelectron imaging measurements with an extremely short temporal resolution.![]()
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Affiliation(s)
- Nikoleta Kotsina
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Christian Brahms
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Sebastian L. Jackson
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - John C. Travers
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Dave Townsend
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
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4
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Carrasco S, Rogan J, Valdivia JA, Sola IR. Anti-alignment driven dynamics in the excited states of molecules under strong fields. Phys Chem Chem Phys 2021; 23:1936-1942. [PMID: 33459314 DOI: 10.1039/d0cp05692h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We develop two novel models of the H2+ molecule and its isotopes from which we assess quantum-mechanically and semi-classically whether the molecule anti-aligns with the field in the first excited electronic state. The results from both models allow us to predict anti-alignment dynamics even for the HD+ isotope, which possesses a permanent dipole moment. The molecule dissociates at angles perpendicular to the field polarization in both the excited and the ground electronic state, as the population is exchanged through a conical intersection. The quantum mechanical dispersion of the initial state is sufficient to cause full dissociation. We conclude that the stabilization of these molecules in the excited state through bond-hardening under a strong field is highly unlikely.
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Affiliation(s)
- Sebastián Carrasco
- Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, 7800024, Santiago, Chile.
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5
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Yang Y, Zheng W, Xie H, Ren L, Xu X, Liang Y. Theoretical study on adiabatic electron affinity of fatty acids. NEW J CHEM 2021. [DOI: 10.1039/d1nj02456f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The AEA of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids with typical substituents were calculated by the ωB97X method.
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Affiliation(s)
- Yaxin Yang
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
| | - Wenrui Zheng
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
| | - Hongyun Xie
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
| | - Lufei Ren
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
| | - Xiaofei Xu
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
| | - Yingning Liang
- College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai, 201620, China
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6
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Schüppel F, Schnappinger T, Bäuml L, de Vivie-Riedle R. Waveform control of molecular dynamics close to a conical intersection. J Chem Phys 2020; 153:224307. [PMID: 33317296 DOI: 10.1063/5.0031398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Conical intersections are ubiquitous in chemical systems but, nevertheless, extraordinary points on the molecular potential energy landscape. They provide ultra-fast radiationless relaxation channels, their topography influences the product branching, and they equalize the timescales of the electron and nuclear dynamics. These properties reveal optical control possibilities in the few femtosecond regime. In this theoretical study, we aim to explore control options that rely on the carrier envelope phase of a few-cycle IR pulse. The laser interaction creates an electronic superposition just before the wave packet reaches the conical intersection. The imprinted phase information is varied by the carrier envelope phase to influence the branching ratio after the conical intersection. We test and analyze this scenario in detail for a model system and show to what extent it is possible to transfer this type of control to a realistic system like uracil.
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Affiliation(s)
| | | | - Lena Bäuml
- Department of Chemistry, LMU Munich, D-81377 Munich, Germany
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7
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van den Berg JL, Neumann KI, Harrison JA, Weir H, Hohenstein EG, Martinez TJ, Zare RN. Strong, Nonresonant Radiation Enhances Cis- Trans Photoisomerization of Stilbene in Solution. J Phys Chem A 2020; 124:5999-6008. [PMID: 32585098 DOI: 10.1021/acs.jpca.0c02732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Previously, it has been demonstrated that external electric fields may be used to exert control over chemical reactivity. In this study, the impact of a strong, nonresonant IR field (1064 nm) on the photoisomerization of cis-stilbene is investigated in cyclohexane solution. The design of a suitable reaction vessel for characterization of this effect is presented. The electric field supplied by the pulsed, near-IR radiation (εl = 4.5 × 107 V/cm) enhances the cis → trans photoisomerization yield at the red edge of the absorption spectrum (wavelengths between 337 and 340 nm). Within the microliter focal volume, up to 75% of all cis-stilbene molecules undergo isomerization to trans-stilbene in the strong electric-field environment, indicating a significant increase relative to the 35% yield of trans-stilbene under field-free conditions. This result correlates with a 1-3% enhancement in the trans-stilbene concentration throughout the bulk solution. Theoretical analysis suggests that the observed change is the result of dynamic Stark shifting of the ground and first excited states, leading to a significant redshift in cis-stilbene's absorption spectrum. The predicted increase in the absorption cross section in this range of excitation wavelengths is qualitatively consistent with the experimental increase in trans-stilbene production.
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Affiliation(s)
- Jana L van den Berg
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Kallie Ilene Neumann
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - John A Harrison
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,Chemistry, School of Natural and Computational Sciences, Massey University Auckland, Private Bag 102904, Auckland 4442, New Zealand
| | - Hayley Weir
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Edward G Hohenstein
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Todd J Martinez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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8
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Liekhus-Schmaltz C, Zhu X, McCracken GA, Cryan JP, Martinez TJ, Bucksbaum PH. Strictly non-adiabatic quantum control of the acetylene dication using an infrared field. J Chem Phys 2020; 152:184302. [DOI: 10.1063/5.0007058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chelsea Liekhus-Schmaltz
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Xiaolei Zhu
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Gregory A. McCracken
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - James P. Cryan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Todd J. Martinez
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Philip H. Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
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9
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Wei Z, Li J, Zhang H, Lu Y, Yang M, Loh ZH. Ultrafast dissociative ionization and large-amplitude vibrational wave packet dynamics of strong-field-ionized di-iodomethane. J Chem Phys 2019; 151:214308. [PMID: 31822095 DOI: 10.1063/1.5132967] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We employ few-cycle pulses to strong-field-ionize di-iodomethane (CH2I2) and femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy to investigate the subsequent ultrafast dissociative ionization and vibrational wave packet dynamics. Probing in the spectral region of the I 4d core-level transitions, the time-resolved XUV differential absorption spectra reveal the population of several electronic states of CH2I2 + by strong-field ionization. Global analysis reveals three distinct time scales for the observed dynamics: 20 ± 2 fs, 49 ± 6 fs, and 157 ± 9 fs, ascribed to relaxation of the CH2I2 + parent ion from the Franck-Condon region, dissociation of high-lying excited states of CH2I2 + to I+ (3P2), CH2I, and I2 + (2Π3/2,g), and dissociation of CH2I2 + to I (2P3/2) and CH2I+, respectively. Oscillatory features in the time-resolved XUV differential absorption spectra point to the generation of vibrational wave packets in both the residual CH2I2 and the CH2I2 + parent ion. Analysis of the oscillation frequencies and phases reveals, in the case of neutral CH2I2, C-I symmetric stretching induced by bond softening and I-C-I bending driven by a combination of bond softening and R-selective depletion. In the case of CH2I2 +, both the fundamental and first overtone frequencies of the I-C-I bending mode are observed, indicating large-amplitude I-C-I bending motion, in good agreement with results obtained from ab initio simulations of the XUV transition energy along the I-C-I bend coordinate. These results show that femtosecond XUV absorption spectroscopy is well-suited for studying ultrafast photodissociation and vibrational wave packet dynamics.
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Affiliation(s)
- Zhengrong Wei
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jialin Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Huimin Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Yunpeng Lu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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10
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Mandal A, Huo P. Investigating New Reactivities Enabled by Polariton Photochemistry. J Phys Chem Lett 2019; 10:5519-5529. [PMID: 31475529 DOI: 10.1021/acs.jpclett.9b01599] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We perform quantum dynamics simulations to investigate new chemical reactivities enabled by cavity quantum electrodynamics. The quantum light-matter interactions between the molecule and the quantized radiation mode inside an optical cavity create a set of hybridized electronic-photonic states, so-called polaritons. The polaritonic states adapt the curvatures from both the ground and the excited electronic states, opening up new possibilities to control photochemical reactions by exploiting intrinsic quantum behaviors of light-matter interactions. With quantum dynamics simulations, we demonstrate that the selectivity of a model photoisomerization reaction can be controlled by tuning the photon frequency of the cavity mode or the light-matter coupling strength, providing new ways to manipulate chemical reactions via the light-matter interaction. We further investigate collective quantum effects enabled by coupling the quantized radiation mode to multiple molecules. Our results suggest that in the resonance case, a photon is recycled among molecules to enable multiple excited state reactions, thus effectively functioning as a catalyst. In the nonresonance case, molecules emit and absorb virtual photons to initiate excited state reactions through fundamental quantum electrodynamics processes. These results from quantum dynamics simulations reveal basic principles of polariton photochemistry as well as promising reactivities that take advantage of intrinsic quantum behaviors of photons.
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Affiliation(s)
- Arkajit Mandal
- Department of Chemistry , University of Rochester , 120 Trustee Road , Rochester , New York 14627 , United States
| | - Pengfei Huo
- Department of Chemistry , University of Rochester , 120 Trustee Road , Rochester , New York 14627 , United States
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11
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Dey D, Tiwari AK, Henriksen NE. Coherent control of selective bond breaking: HOD in the A∼-state revisited. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2018.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Thomas EF, Henriksen NE. Breaking dynamic inversion symmetry in a racemic mixture using simple trains of laser pulses. J Chem Phys 2019; 150:024301. [PMID: 30646704 DOI: 10.1063/1.5063536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent advances in ultrafast laser technology hint at the possibility of using shaped pulses to generate deracemization via selective enantiomeric conversion; however, experimental implementation remains a challenge and has not yet been achieved. Here, we describe an experiment that can be considered an accessible intermediate step on the road towards achieving laser induced deracemization in a laboratory. Our approach consists of driving a racemic mixture of 3D oriented 3,5-difluoro-3', 5'-dibromobiphenyl (F2H3C6-C6H3Br2) molecules with a simple train of Gaussian pulses with alternating polarization axes. We use arguments related to the geometry of the field/molecule interaction to illustrate why this will increase the amplitude of the torsional oscillations between the phenyl rings while simultaneously breaking the inversion symmetry of the dynamics between the left- and right-handed enantiomeric forms, two crucial requirements for achieving deracemization. We verify our approach using numerical simulations and show that it leads to significant and experimentally measurable differences in the internal enantiomeric structures when detected by Coulomb explosion imaging.
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Affiliation(s)
- Esben F Thomas
- Department of Chemistry, Technical University of Denmark, Building 206, DK-2800 Kongens Lyngby, Denmark
| | - Niels E Henriksen
- Department of Chemistry, Technical University of Denmark, Building 206, DK-2800 Kongens Lyngby, Denmark
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13
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Tutunnikov I, Gershnabel E, Gold S, Averbukh IS. Selective Orientation of Chiral Molecules by Laser Fields with Twisted Polarization. J Phys Chem Lett 2018; 9:1105-1111. [PMID: 29417812 DOI: 10.1021/acs.jpclett.7b03416] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We explore a pure optical method for enantioselective orientation of chiral molecules by means of laser fields with twisted polarization. Several field implementations are considered, including a pair of delayed, cross-polarized laser pulses, an optical centrifuge, and polarization-shaped pulses. We show that these schemes lead to out-of-phase time-dependent dipole signals for different enantiomers, and we also predict a substantial permanent molecular orientation persisting long after the laser fields are over. The underlying classical orientation mechanism common to all of these fields is discussed, and its operation is demonstrated for a range of chiral molecules of various complexity: hydrogen thioperoxide (HSOH), propylene oxide (CH3CHCH2O), and ethyl oxirane (CH3CH2CHCH2O). The presented results demonstrate generality, versatility, and robustness of this optical method for manipulating molecular enantiomers in the gas phase.
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Affiliation(s)
- Ilia Tutunnikov
- Department of Chemical and Biological Physics, Weizmann Institute of Science , Rehovot 7610001, Israel
| | - Erez Gershnabel
- Department of Chemical and Biological Physics, Weizmann Institute of Science , Rehovot 7610001, Israel
| | - Shachar Gold
- Department of Chemical and Biological Physics, Weizmann Institute of Science , Rehovot 7610001, Israel
| | - Ilya Sh Averbukh
- Department of Chemical and Biological Physics, Weizmann Institute of Science , Rehovot 7610001, Israel
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14
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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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15
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Chang BY, Shin S, Engel V, Sola IR. Geometrical Optimization Approach to Isomerization: Models and Limitations. J Phys Chem A 2017; 121:8280-8287. [DOI: 10.1021/acs.jpca.7b08767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bo Y. Chang
- School
of Chemistry (BK21), Seoul National University, Seoul 08826, Republic of Korea
| | - Seokmin Shin
- School
of Chemistry (BK21), Seoul National University, Seoul 08826, Republic of Korea
| | - Volker Engel
- Institut
für Physikalische und Theoretische Chemie, Universität Würzburg, 97074 Würzburg, Germany
| | - Ignacio R. Sola
- Departamento
de Química Física I, Universidad Complutense, 28040 Madrid, Spain
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16
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Femtochemistry in the electronic ground state: Dynamic Stark control of vibrational dynamics. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Thomas EF, Henriksen NE. Phase-Modulated Nonresonant Laser Pulses Can Selectively Convert Enantiomers in a Racemic Mixture. J Phys Chem Lett 2017; 8:2212-2219. [PMID: 28467085 DOI: 10.1021/acs.jpclett.7b00662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Deracemization occurs when a racemic molecular mixture is transformed into a mixture containing an excess of a single enantiomer. Recent advances in ultrafast laser technology hint at the possibility of using shaped pulses to generate deracemization via selective enantiomeric conversion; however, experimental implementation remains a challenge and has not yet been achieved. Here we suggest a simple, yet novel approach to laser-induced enantiomeric conversion based on dynamic Stark control. We demonstrate theoretically that current laser and optical technology can be used to generate a pair of phase-modulated, nonresonant, linearly polarized Gaussian laser pulses that can selectively deracemize a racemic mixture of 3D-oriented, 3,5-difluoro-3',5'-dibromobiphenyl (F2H3C6-C6H3Br2) molecules, the laser-induced dynamics of which are well studied experimentally. These results strongly suggest that designing a closed-loop coherent control scheme based on this methodology may lead to the first-ever achievement of enantiomeric conversion via coherent laser light in a laboratory setting.
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Affiliation(s)
- Esben F Thomas
- Department of Chemistry, Technical University of Denmark , Building 206, DK-2800 Kongens Lyngby, Denmark
| | - Niels E Henriksen
- Department of Chemistry, Technical University of Denmark , Building 206, DK-2800 Kongens Lyngby, Denmark
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18
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Liekhus-Schmaltz C, McCracken GA, Kaldun A, Cryan JP, Bucksbaum PH. Coherent control using kinetic energy and the geometric phase of a conical intersection. J Chem Phys 2016; 145:144304. [DOI: 10.1063/1.4964392] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chelsea Liekhus-Schmaltz
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Gregory A. McCracken
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Andreas Kaldun
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - James P. Cryan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Philip H. Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
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19
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Sampedro P, Chang BY, Sola IR. Nonresonant electronic transitions induced by vibrational motion in light-induced potentials. Phys Chem Chem Phys 2016; 18:25265-25270. [PMID: 27711509 DOI: 10.1039/c6cp04761k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We find a new mechanism of electronic population inversion using strong femtosecond pulses, where the transfer is mediated by vibrational motion on a light-induced potential. The process can be achieved with a single pulse tuning its frequency to the red of the Franck-Condon window. We show the determinant role that the gradient of the transition dipole moment can play on the dynamics, and extend the method to multiphoton processes with odd number of pulses. As an example, we show how the scheme can be applied to population inversion in Na2.
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Affiliation(s)
- Pablo Sampedro
- Departamento de Química Física, Universidad Complutense, 28040 Madrid, Spain.
| | - Bo Y Chang
- School of Chemistry (BK21+), Seoul National University, Seoul 08826, Republic of Korea
| | - Ignacio R Sola
- Departamento de Química Física, Universidad Complutense, 28040 Madrid, Spain.
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20
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Waldl M, Oppel M, González L. Controlling the Excited-State Dynamics of Nuclear Spin Isomers Using the Dynamic Stark Effect. J Phys Chem A 2016; 120:4907-14. [PMID: 26840424 DOI: 10.1021/acs.jpca.5b12542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stark control of chemical reactions uses intense laser pulses to distort the potential energy surfaces of a molecule, thus opening new chemical pathways. We use the concept of Stark shifts to convert a local minimum into a local maximum of the potential energy surface, triggering constructive and destructive wave-packet interferences, which then induce different dynamics on nuclear spin isomers in the electronically excited state of a quinodimethane derivative. Model quantum-dynamical simulations on reduced dimensionality using optimized ultrashort laser pulses demonstrate a difference of the excited-state dynamics of two sets of nuclear spin isomers, which ultimately can be used to discriminate between these isomers.
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Affiliation(s)
- Maria Waldl
- Institut für Theoretische Chemie, Universität Wien , Währinger Str. 17, 1090 Wien, Austria
| | - Markus Oppel
- Institut für Theoretische Chemie, Universität Wien , Währinger Str. 17, 1090 Wien, Austria
| | - Leticia González
- Institut für Theoretische Chemie, Universität Wien , Währinger Str. 17, 1090 Wien, Austria
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21
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Thomas EF, Henriksen NE. Non-resonant dynamic stark control of vibrational motion with optimized laser pulses. J Chem Phys 2016; 144:244307. [PMID: 27369515 DOI: 10.1063/1.4954663] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The term dynamic Stark control (DSC) has been used to describe methods of quantum control related to the dynamic Stark effect, i.e., a time-dependent distortion of energy levels. Here, we employ analytical models that present clear and concise interpretations of the principles behind DSC. Within a linearly forced harmonic oscillator model of vibrational excitation, we show how the vibrational amplitude is related to the pulse envelope, and independent of the carrier frequency of the laser pulse, in the DSC regime. Furthermore, we shed light on the DSC regarding the construction of optimal pulse envelopes - from a time-domain as well as a frequency-domain perspective. Finally, in a numerical study beyond the linearly forced harmonic oscillator model, we show that a pulse envelope can be constructed such that a vibrational excitation into a specific excited vibrational eigenstate is accomplished. The pulse envelope is constructed such that high intensities are avoided in order to eliminate the process of ionization.
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Affiliation(s)
- Esben F Thomas
- Department of Chemistry, Technical University of Denmark, Building 207, DK-2800 Kongens Lyngby, Denmark
| | - Niels E Henriksen
- Department of Chemistry, Technical University of Denmark, Building 207, DK-2800 Kongens Lyngby, Denmark
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22
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Sampedro P, Chang BY, Sola IR. Protecting and accelerating adiabatic passage with time-delayed pulse sequences. Phys Chem Chem Phys 2016; 18:13443-8. [PMID: 27125342 DOI: 10.1039/c6cp01680d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using numerical simulations of two-photon electronic absorption with femtosecond pulses in Na2 we show that: (i) it is possible to avoid the characteristic saturation or dumped Rabi oscillations in the yield of absorption by time-delaying the laser pulses; (ii) it is possible to accelerate the onset of adiabatic passage by using the vibrational coherence starting in a wave packet; and (iii) it is possible to prepare the initial wave packet in order to achieve full state-selective transitions with broadband pulses. The findings can be used, for instance, to achieve ultrafast adiabatic passage by light-induced potentials and understand its intrinsic robustness.
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Affiliation(s)
- Pablo Sampedro
- Departamento de Química Física, Universidad Complutense, 28040 Madrid, Spain.
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23
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Chang BY, Shin S, Sola IR. “Stirred, Not Shaken”: Vibrational Coherence Can Speed Up Electronic Absorption. J Phys Chem A 2015; 119:9091-7. [DOI: 10.1021/acs.jpca.5b05994] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bo Y. Chang
- School
of Chemistry (BK21+), Seoul National University, Seoul 151-747, Republic of Korea
| | - Seokmin Shin
- School
of Chemistry (BK21+), Seoul National University, Seoul 151-747, Republic of Korea
| | - Ignacio R. Sola
- Departamento
de Química Física, Universidad Complutense, 28040 Madrid, Spain
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24
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Solá IR, González-Vázquez J, de Nalda R, Bañares L. Strong field laser control of photochemistry. Phys Chem Chem Phys 2015; 17:13183-200. [PMID: 25835746 DOI: 10.1039/c5cp00627a] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Strong ultrashort laser pulses have opened new avenues for the manipulation of photochemical processes like photoisomerization or photodissociation. The presence of light intense enough to reshape the potential energy surfaces may steer the dynamics of both electrons and nuclei in new directions. A controlled laser pulse, precisely defined in terms of spectrum, time and intensity, is the essential tool in this type of approach to control chemical dynamics at a microscopic level. In this Perspective we examine the current strategies developed to achieve control of chemical processes with strong laser fields, as well as recent experimental advances that demonstrate that properties like the molecular absorption spectrum, the state lifetimes, the quantum yields and the velocity distributions in photodissociation processes can be controlled by the introduction of carefully designed strong laser fields.
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Affiliation(s)
- Ignacio R Solá
- Departamento de Química Física I (Unidad Asociada de I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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25
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Chang BY, Shin S, Sola IR. Ultrafast Population Inversion without the Strong Field Catch: The Parallel Transfer. J Phys Chem Lett 2015; 6:1724-1728. [PMID: 26263340 DOI: 10.1021/acs.jpclett.5b00651] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Quantum systems with sublevel structures, like molecules, prevent full population inversion from one manifold of sublevels to the other using ultrafast resonant pulses. We explain the mechanism by which this population transfer is blocked. We then develop a novel concept of geometric control, assuming full or partial coherent manipulation within the manifolds, and show that by preparing specific coherent superpositions in the initial manifold, full population inversion or full population blockade, that is, laser transparency, can be achieved. By properly choosing the relative phases of the initial state, one can interfere in the stimulated emission process, changing the pattern of Rabi oscillations so that full population inversion to the excited electronic state can be achieved almost regardless of the pulse intensity after a minimal threshold value. This is the basis of a novel control mechanism, termed parallel transfer.
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Affiliation(s)
- Bo Y Chang
- †School of Chemistry (BK21+), Seoul National University, Seoul 151-747, Republic of Korea
| | - Seokmin Shin
- †School of Chemistry (BK21+), Seoul National University, Seoul 151-747, Republic of Korea
| | - Ignacio R Sola
- ‡Departamento de Quı́mica Fı́sica, Universidad Complutense, 28040 Madrid, Spain
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26
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27
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Christensen L, Nielsen JH, Brandt CB, Madsen CB, Madsen LB, Slater CS, Lauer A, Brouard M, Johansson MP, Shepperson B, Stapelfeldt H. Dynamic stark control of torsional motion by a pair of laser pulses. PHYSICAL REVIEW LETTERS 2014; 113:073005. [PMID: 25170706 DOI: 10.1103/physrevlett.113.073005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Indexed: 06/03/2023]
Abstract
The torsional motion of a molecule composed of two substituted benzene rings, linked by a single bond, is coherently controlled by a pair of strong (3×10^{13} W cm^{-2}), nonresonant (800 nm) 200-fs-long laser pulses-both linearly polarized perpendicular to the single-bond axis. If the second pulse is sent at the time when the two benzene rings rotate toward (away from) each other the amplitude of the torsion is strongly enhanced (reduced). The torsional motion persists for more than 150 ps corresponding to approximately 120 torsional oscillations. Our calculations show that the key to control is the strong transient modification of the natural torsional potential by the laser-induced dynamic Stark effect.
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Affiliation(s)
- Lauge Christensen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Jens H Nielsen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Christian B Brandt
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Christian B Madsen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Lars Bojer Madsen
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Craig S Slater
- Department of Chemistry, University of Oxford, the Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Alexandra Lauer
- Department of Chemistry, University of Oxford, the Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Mark Brouard
- Department of Chemistry, University of Oxford, the Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Mikael P Johansson
- Department of Chemistry, Laboratory for Instruction in Swedish, University of Helsinki, A.I. Virtanens Plats 1, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Benjamin Shepperson
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Henrik Stapelfeldt
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
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28
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Parker SM, Smeu M, Franco I, Ratner MA, Seideman T. Molecular junctions: can pulling influence optical controllability? NANO LETTERS 2014; 14:4587-4591. [PMID: 25072807 DOI: 10.1021/nl501629c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We suggest the combination of single molecule pulling and optical control as a way to enhance control over the electron transport characteristics of a molecular junction. We demonstrate using a model junction consisting of biphenyl-dithiol coupled to gold contacts. The junction is pulled while optically manipulating the dihedral angle between the two rings. Quantum dynamics simulations show that molecular pulling enhances the degree of control over the dihedral angle and hence over the transport properties.
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Affiliation(s)
- Shane M Parker
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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29
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González L, Marquetand P, Richter M, González-Vázquez J, Sola I. Ultrafast Laser-Induced Processes Described by Ab Initio Molecular Dynamics. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/978-3-319-02051-8_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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30
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Ruiz-Barragan S, Blancafort L. Photophysics of fulvene under the non-resonant stark effect. Shaping the conical intersection seam. Faraday Discuss 2013; 163:497-512; discussion 513-43. [PMID: 24020219 DOI: 10.1039/c3fd20155d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We introduce a mechanistic strategy to control the excited state lifetime of fulvene based on shaping the topography of an extended seam of intersection with the non-resonant dynamic Stark effect. Fulvene has a very short excited state lifetime due to an energetically accessible seam of intersection which lies along the methylene torsion coordinate, and the initial decay occurs at the seam segment around the planar conical intersection structure. We have followed a three-step approach to simulate the control. First, we have calculated the effect of a non-resonant electric field on the potential energy surface at the ab initio level, including the field in a self-consistent way. The relative energy of the planar segment of the seam is increased by the non-resonant field. In the second step we simulate the control carrying out MCTDH quantum dynamics propagations under a static non-resonant field to derive the main control mechanisms. At moderately intense fields (epsilon < or = 0.03 a.u.) the decay is faster as compared to the field free case because the vibrational overlap between the excited and ground state vibrational functions is increased. However, at more intense fields (epsilon = 0.04 a.u.) the planar conical intersection is energetically inaccessible and the decay occurs at a slower time scale, at the segment of the seam with more twisted geometries. In the third step, the control over the dynamics is exerted with a non-resonant dynamic field. The acceleration of the decay due to the improved vibrational overlap does not occur, but the decay can be made slower with a dynamic field of 0.08 a.u. The results show the viability of our approach to control the photophysics shaping the topology of the conical intersection seam, and they prove that the extended nature of the seam is crucial for simulating and understanding the control.
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Affiliation(s)
- Sergi Ruiz-Barragan
- Institut de Quimica Computacional and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain
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31
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Chatterley AS, Roberts GM, Stavros VG. Timescales for adiabatic photodissociation dynamics from the à state of ammonia. J Chem Phys 2013; 139:034318. [DOI: 10.1063/1.4811672] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Ashwell BA, Ramakrishna S, Seideman T. Laser-driven torsional coherences. J Chem Phys 2013; 138:044310. [DOI: 10.1063/1.4773009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Calvert CR, Belshaw L, Duffy MJ, Kelly O, King RB, Smyth AG, Kelly TJ, Costello JT, Timson DJ, Bryan WA, Kierspel T, Rice P, Turcu ICE, Cacho CM, Springate E, Williams ID, Greenwood JB. LIAD-fs scheme for studies of ultrafast laser interactions with gas phase biomolecules. Phys Chem Chem Phys 2012; 14:6289-97. [PMID: 22322861 DOI: 10.1039/c2cp23840c] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Laser induced acoustic desorption (LIAD) has been used for the first time to study the parent ion production and fragmentation mechanisms of a biological molecule in an intense femtosecond (fs) laser field. The photoacoustic shock wave generated in the analyte substrate (thin Ta foil) has been simulated using the hydrodynamic HYADES code, and the full LIAD process has been experimentally characterised as a function of the desorption UV-laser pulse parameters. Observed neutral plumes of densities >10(9) cm(-3) which are free from solvent or matrix contamination demonstrate the suitability and potential of the source for studying ultrafast dynamics in the gas phase using fs laser pulses. Results obtained with phenylalanine show that through manipulation of fundamental femtosecond laser parameters (such as pulse length, intensity and wavelength), energy deposition within the molecule can be controlled to allow enhancement of parent ion production or generation of characteristic fragmentation patterns. In particular by reducing the pulse length to a timescale equivalent to the fastest vibrational periods in the molecule, we demonstrate how fragmentation of the molecule can be minimised whilst maintaining a high ionisation efficiency.
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Affiliation(s)
- C R Calvert
- Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, Northern Ireland
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34
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Bajo JJ, González-Vázquez J, Sola IR, Santamaria J, Richter M, Marquetand P, González L. Mixed quantum-classical dynamics in the adiabatic representation to simulate molecules driven by strong laser pulses. J Phys Chem A 2012; 116:2800-7. [PMID: 22168132 DOI: 10.1021/jp208997r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dynamics of molecules under strong laser pulses is characterized by large Stark effects that modify and reshape the electronic potentials, known as laser-induced potentials (LIPs). If the time scale of the interaction is slow enough that the nuclear positions can adapt to these externally driven changes, the dynamics proceeds by adiabatic following, where the nuclei gain very little kinetic energy during the process. In this regime we show that the molecular dynamics can be simulated quite accurately by a semiclassical surface-hopping scheme formulated in the adiabatic representation. The nuclear motion is then influenced by the gradients of the laser-modified potentials, and nonadiabatic couplings are seen as transitions between the LIPs. As an example, we simulate the process of adiabatic passage by light induced potentials in Na(2) using the surface-hopping technique both in the diabatic representation based on molecular potentials and in the adiabatic representation based on LIPs, showing how the choice of the representation is crucial in reproducing the results obtained by exact quantum dynamical calculations.
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Affiliation(s)
- Juan José Bajo
- Departamento de Química-Física I, Universidad Complutense de Madrid, 28040 Madrid, Spain
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35
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Kinzel D, Marquetand P, González L. Stark Control of a Chiral Fluoroethylene Derivative. J Phys Chem A 2011; 116:2743-9. [DOI: 10.1021/jp207947x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Philipp Marquetand
- Institute of Theoretical Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
| | - Leticia González
- Institute of Theoretical Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
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36
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Abstract
Ab initio classical molecular dynamics calculations have been used to simulate the dissociation of H(2)NCH(2+) in a strong laser field. The frequencies of the continuous oscillating electric field were chosen to be ω = 0.02, 0.06, and 0.18 au (2280, 760, and 253 nm, respectively). The field had a maximum strength of 0.03 au (3.2 × 10(13) W cm(-2)) and was aligned with the CN bond. Trajectories were started with 100 kcal/mol of vibrational energy above zero point and were integrated for up to 600 fs at the B3LYP/6-311G(d,p) level of theory. A total of 200 trajectories were calculated for each of the three different frequencies and without a field. Two dissociation channels are observed: HNCH(+) + H(+) and H(2)NC(+) + H(+). About one-half to two-thirds of the H(+) dissociations occurred directly, while the remaining indirect dissociations occurred at a slower rate with extensive migration of H(+) between C and N. The laser field increased the initial dissociation rate by a factor of ca. 1.4 and decreased the half-life by a factor of ca. 0.75. The effects were similar at each of the three frequencies. The HNCH(+) to H(2)NC(+) branching ratio decreased from 10.6:1 in the absence of the field to an average of 8.4:1 in the laser field. The changes in the rates and branching ratios can be attributed to the laser field lowering the reaction barriers as a result of a difference in polarizability of the reactant and transition states.
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Affiliation(s)
- Jia Zhou
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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37
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Bustard PJ, Wu G, Lausten R, Townsend D, Walmsley LA, Stolow A, Sussman BJ. From molecular control to quantum technology with the dynamic Stark effect. Faraday Discuss 2011; 153:321-42; discussion 395-413. [PMID: 22452088 DOI: 10.1039/c1fd00067e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The non-resonant dynamic Stark effect is a powerful and general way of manipulating ultrafast processes in atoms, molecules, and solids with exquisite precision. We discuss the physics behind this effect, and demonstrate its efficacy as a method of control in a variety of systems. These applications range from the control of molecular rotational dynamics to the manipulation of chemical reaction dynamics, and from the suppression of vacuum fluctuation effects in coherent preparation of matter, to the dynamic generation of bandwidth for storage of broadband quantum states of light.
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Affiliation(s)
- Philip J Bustard
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
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