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Morassut C, Ravindran A, Ciavardini A, Luppi E, De Ninno G, Coccia E. High-Harmonic Generation Spectroscopy of Gas-Phase Bromoform. J Phys Chem A 2024; 128:2015-2024. [PMID: 38469750 DOI: 10.1021/acs.jpca.3c07699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
High-Harmonic Generation (HHG) spectra of randomly aligned bromoform (CHBr3) molecules have been experimentally measured and theoretically simulated at various laser pulse intensities. From the experiments, we obtained a significant number of harmonics that goes beyond the cutoff limit predicted by the three-step model (3SM) with ionization from HOMO. To interpret the experiment, we resorted to real-time time-dependent configuration interaction with single excitations. We found that electronic bound states provide an appreciable contribution to the harmonics. More in detail, we analyzed the electron dynamics by decomposing the HHG signal in terms of single molecular-orbital contributions, to explain the appearance of harmonics around 20-30 eV beyond the expected cutoff due to HOMO. HHG spectra can be therefore explained by considering the contribution at high energy of HOMO-6 and HOMO-9, thus indicating a complex multiple-orbital strong-field dynamics. However, even though the presence of the bromoform cation should be not enough to produce such a signal, we could not exclude a priori that the origin of harmonics in the H29-H45 to be due to the cation, which has more energetic ionization channels.
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Affiliation(s)
- Chiara Morassut
- Laboratoire de Chimie Théorique, Sorbonne Université, CNRS, Paris F-75005, France
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
| | - Arun Ravindran
- Laboratory of Quantum Optics, University of Nova Gorica, Si-5270 Ajdovščina, Slovenija
| | - Alessandra Ciavardini
- Laboratory of Quantum Optics, University of Nova Gorica, Si-5270 Ajdovščina, Slovenija
| | - Eleonora Luppi
- Laboratoire de Chimie Théorique, Sorbonne Université, CNRS, Paris F-75005, France
| | - Giovanni De Ninno
- Laboratory of Quantum Optics, University of Nova Gorica, Si-5270 Ajdovščina, Slovenija
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14-km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
| | - Emanuele Coccia
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, Italy
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Bäuml L, Rott F, Schnappinger T, de Vivie-Riedle R. Following the Nonadiabatic Ultrafast Dynamics of Uracil via Simulated X-ray Absorption Spectra. J Phys Chem A 2023; 127:9787-9796. [PMID: 37955656 DOI: 10.1021/acs.jpca.3c06509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
The nucleobase uracil exhibits high photostability due to ultrafast relaxation processes mediated by conical intersections (CoIns), where the interplay between nuclear and electron dynamics becomes crucial. In our previous study, we observed seemingly long-lived traces of electronic coherence for the relaxation process through the S2/S1 CoIn by applying our ansatz for coupled nuclear and electron dynamics in molecules (NEMol). In this work, we theoretically investigate how time-dependent transient X-ray absorption spectroscopy can be used to observe this ultrafast dynamics. Therefore, we calculated X-ray absorption spectra (XAS) for the oxygen K-edge, using a multireference protocol in combination with NEMol dynamics. Thus, we have access to both the transient XAS based on the nuclear wavepacket dynamics and the modulation of the signals caused by the electronic coherence induced by the excitation process and the presence of a CoIn seam. In both cases, we were able to qualitatively predict its influence on the resulting XAS.
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Affiliation(s)
- Lena Bäuml
- Department of Chemistry, LMU Munich, Munich 81377, Germany
| | - Florian Rott
- Department of Chemistry, LMU Munich, Munich 81377, Germany
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Toulson BW, Hait D, Faccialà D, Neumark DM, Leone SR, Head-Gordon M, Gessner O. Probing C-I bond fission in the UV photochemistry of 2-iodothiophene with core-to-valence transient absorption spectroscopy. J Chem Phys 2023; 159:034304. [PMID: 37466229 DOI: 10.1063/5.0151629] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/29/2023] [Indexed: 07/20/2023] Open
Abstract
The UV photochemistry of small heteroaromatic molecules serves as a testbed for understanding fundamental photo-induced chemical transformations in moderately complex compounds, including isomerization, ring-opening, and molecular dissociation. Here, a combined experimental-theoretical study of 268 nm UV light-induced dynamics in 2-iodothiophene (C4H3IS) is performed. The dynamics are experimentally monitored with a femtosecond extreme ultraviolet (XUV) probe that measures iodine N-edge 4d core-to-valence transitions. Experiments are complemented by density functional theory calculations of both the pump-pulse induced valence excitations and the XUV probe-induced core-to-valence transitions. Possible intramolecular relaxation dynamics are investigated by ab initio molecular dynamics simulations. Gradual absorption changes up to ∼0.5 to 1 ps after excitation are observed for both the parent molecular species and emerging iodine fragments, with the latter appearing with a characteristic rise time of 160 ± 30 fs. Comparison of spectral intensities and energies with the calculations identifies an iodine dissociation pathway initiated by a predominant π → π* excitation. In contrast, initial excitation to a nearby n⟂ → σ* state appears unlikely based on a significantly smaller oscillator strength and the absence of any corresponding XUV absorption signatures. Excitation to the π → π* state is followed by contraction of the C-I bond, enabling a nonadiabatic transition to a dissociative π→σC-I* state. For the subsequent fragmentation, a relatively narrow bond-length region along the C-I stretch coordinate between 230 and 280 pm is identified, where the transition between the parent molecule and the thienyl radical + iodine atom products becomes prominent in the XUV spectrum due to rapid localization of two singly occupied molecular orbitals on the two fragments.
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Affiliation(s)
- Benjamin W Toulson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Diptarka Hait
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Davide Faccialà
- CNR-Istituto di Fotonica e Nanotecnologie (CNR-IFN), 20133 Milano, Italy
| | - Daniel M Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Stephen R Leone
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Martin Head-Gordon
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Oliver Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Yoshiki A, Sugino Y, Tendo S, Fukami R, Kohguchi H, Yamasaki K. Rate coefficients for the CH(X2Π) + CHX3 (X = Cl and Br) reactions and the propensity of the reactions of CH with halomethanes. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bhattacharyya S, Borne K, Ziaee F, Pathak S, Wang E, Venkatachalam AS, Li X, Marshall N, Carnes KD, Fehrenbach CW, Severt T, Ben-Itzhak I, Rudenko A, Rolles D. Strong-Field-Induced Coulomb Explosion Imaging of Tribromomethane. J Phys Chem Lett 2022; 13:5845-5853. [PMID: 35727076 PMCID: PMC9252187 DOI: 10.1021/acs.jpclett.2c01007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
The Coulomb explosion of tribromomethane (bromoform, CHBr3) induced by 28 fs near-infrared laser pulses is investigated by three-dimensional coincidence ion momentum imaging. We focus on the fragmentation into three, four, and five ionic fragments measured in coincidence and present different ways of visualizing the three-dimensional momentum correlations. We show that the experimentally observed momentum correlations for 4- and 5-fold coincidences are well reproduced by classical Coulomb explosion simulations and contain information about the structure of the parent molecule that could be used to differentiate structural isomers formed, for example, in a pump-probe experiment. Our results thus provide a clear path toward visualizing structural dynamics in polyatomic molecules by strong-field-induced Coulomb explosion imaging.
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Detection of atomic bromine (4p5 2P ; J = 1/2, 3/2) by two-photon laser-induced vacuum ultraviolet emission. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2021.139253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bhattacharyya S, Borne K, Ziaee F, Pathak S, Wang E, Venkatachalam AS, Marshall N, Carnes KD, Fehrenbach CW, Severt T, Ben-Itzhak I, Rudenko A, Rolles D. Two- and three-body fragmentation of multiply charged tribromomethane by ultrafast laser pulses. Phys Chem Chem Phys 2022; 24:27631-27644. [DOI: 10.1039/d2cp03089f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This article provides mechanistic insight into the two- and three-body fragmentation dynamics of CHBr3 after strong-field ionization and discusses the possible isomerization of CHBr3 to BrCHBr–Br (iso-CHBr3) prior to the fragmentation.
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Affiliation(s)
- Surjendu Bhattacharyya
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Kurtis Borne
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Farzaneh Ziaee
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Shashank Pathak
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Enliang Wang
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
| | - Anbu Selvam Venkatachalam
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Nathan Marshall
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Kevin D. Carnes
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Charles W. Fehrenbach
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Travis Severt
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Itzik Ben-Itzhak
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Artem Rudenko
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
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Faccialà D, Toulson BW, Gessner O. Removal of correlated background in a high-order harmonic transient absorption spectra with principal component regression. OPTICS EXPRESS 2021; 29:35135-35148. [PMID: 34808953 DOI: 10.1364/oe.435008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate a 40x mean noise power reduction (NPR) in core-to-valence extreme ultraviolet (XUV) femtosecond transient absorption spectroscopy with a high harmonic generation (HHG) light source. An adaptive iteratively reweighted principal component regression (airPCR) is used to analyze and suppress spectrally correlated HHG intensity fluctuations. The technique requires significantly less user input and leads to a higher mean NPR than a previously introduced edge-pixel PCR method that relies on the manual identification of signal-free spectral regions. Both techniques are applied in a time-resolved XUV absorption study of the 2snp1Po (n ≥ 2) autoionizing Rydberg states of helium, demonstrating sub-10-3 optical density sensitivity.
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Lacombe L, Maitra NT. Minimizing the Time-Dependent Density Functional Error in Ehrenfest Dynamics. J Phys Chem Lett 2021; 12:8554-8559. [PMID: 34464148 DOI: 10.1021/acs.jpclett.1c02020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Simulating electron-ion dynamics using time-dependent density functional theory within an Ehrenfest dynamics scheme can be done in two ways that are in principle exact and identical: propagating time-dependent electronic Kohn-Sham equations or propagating electronic coefficients on surfaces obtained from linear-response. We show here that using an approximate functional leads to qualitatively different dynamics in the two approaches. We argue that the latter is more accurate because the functionals are evaluated on domains close to the ground state where currently used approximations perform better. We demonstrate this on an exactly solvable model of charge transfer and discuss implications for time-resolved spectroscopy.
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Affiliation(s)
- Lionel Lacombe
- Department of Physics, Rutgers University, Newark 07102, New Jersey United States
| | - Neepa T Maitra
- Department of Physics, Rutgers University, Newark 07102, New Jersey United States
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Boulanger SA, Zhu L, Tang L, Saha S, Keszler DA, Fang C. Photoinduced Charge Transfer and Bimetallic Bond Dissociation of a Bi-W Complex in Solution. J Phys Chem Lett 2020; 11:7575-7582. [PMID: 32818381 DOI: 10.1021/acs.jpclett.0c02380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organometallic complexes including metal carbonyls have been widely utilized in academic and industrial settings for purposes ranging from teaching basic catalytic reactions to developing state-of-the-art electronic circuits. Characterization of these materials can be obtained via steady-state measurements; however, the intermediate photochemical events remain unclear, hindering effective and rational molecular engineering methods for new materials. We employed femtosecond transient absorption (fs-TA) and ground-state femtosecond stimulated Raman spectroscopy (FSRS) on triphenylbismuth-tungsten pentacarbonyl complex, a solution precursor for bimetallic oxide thin films. Upon 280 nm excitation into a charge-transfer band, an ultrafast bimetallic bond dissociation occurs within ∼140 fs. The subpicosecond nondiffusive solvation events are followed by ∼10 ps (15 ps) methanol (ethanol) complexation of the nascent tungsten pentacarbonyl intermediate, which mainly undergoes vibrational relaxation after crossing into a hot ground state. The trans ligand to axial CO is revealed to play a key role in the electronic and vibrational structure and dynamics of the complex. These findings could power rational design of bimetallic and functional solution precursors for the light-driven nanopatterning of thin films.
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Affiliation(s)
- Sean A Boulanger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Sumit Saha
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Douglas A Keszler
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
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