1
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Hutton L, Moreno Carrascosa A, Prentice AW, Simmermacher M, Runeson JE, Paterson MJ, Kirrander A. Using a multistate mapping approach to surface hopping to predict the ultrafast electron diffraction signal of gas-phase cyclobutanone. J Chem Phys 2024; 160:204307. [PMID: 38814011 DOI: 10.1063/5.0203667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 05/05/2024] [Indexed: 05/31/2024] Open
Abstract
Using the recently developed multistate mapping approach to surface hopping (multistate MASH) method combined with SA(3)-CASSCF(12,12)/aug-cc-pVDZ electronic structure calculations, the gas-phase isotropic ultrafast electron diffraction (UED) of cyclobutanone is predicted and analyzed. After excitation into the n-3s Rydberg state (S2), cyclobutanone can relax through two S2/S1 conical intersections, one characterized by compression of the CO bond and the other by dissociation of the α-CC bond. Subsequent transfer into the ground state (S0) is then achieved via two additional S1/S0 conical intersections that lead to three reaction pathways: α ring-opening, ethene/ketene production, and CO liberation. The isotropic gas-phase UED signal is predicted from the multistate MASH simulations, allowing for a direct comparison to the experimental data. This work, which is a contribution to the cyclobutanone prediction challenge, facilitates the identification of the main photoproducts in the UED signal and thereby emphasizes the importance of dynamics simulations for the interpretation of ultrafast experiments.
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Affiliation(s)
- Lewis Hutton
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Andrés Moreno Carrascosa
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Andrew W Prentice
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Mats Simmermacher
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Johan E Runeson
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Martin J Paterson
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
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2
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Lee Y, Oang KY, Kim D, Ihee H. A comparative review of time-resolved x-ray and electron scattering to probe structural dynamics. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:031301. [PMID: 38706888 PMCID: PMC11065455 DOI: 10.1063/4.0000249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/10/2024] [Indexed: 05/07/2024]
Abstract
The structure of molecules, particularly the dynamic changes in structure, plays an essential role in understanding physical and chemical phenomena. Time-resolved (TR) scattering techniques serve as crucial experimental tools for studying structural dynamics, offering direct sensitivity to molecular structures through scattering signals. Over the past decade, the advent of x-ray free-electron lasers (XFELs) and mega-electron-volt ultrafast electron diffraction (MeV-UED) facilities has ushered TR scattering experiments into a new era, garnering significant attention. In this review, we delve into the basic principles of TR scattering experiments, especially focusing on those that employ x-rays and electrons. We highlight the variations in experimental conditions when employing x-rays vs electrons and discuss their complementarity. Additionally, cutting-edge XFELs and MeV-UED facilities for TR x-ray and electron scattering experiments and the experiments performed at those facilities are reviewed. As new facilities are constructed and existing ones undergo upgrades, the landscape for TR x-ray and electron scattering experiments is poised for further expansion. Through this review, we aim to facilitate the effective utilization of these emerging opportunities, assisting researchers in delving deeper into the intricate dynamics of molecular structures.
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Affiliation(s)
| | - Key Young Oang
- Radiation Center for Ultrafast Science, Korea Atomic Energy Research Institute (KAERI), Daejeon 34057, South Korea
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3
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Makhov DV, Hutton L, Kirrander A, Shalashilin DV. Ultrafast electron diffraction of photoexcited gas-phase cyclobutanone predicted by ab initio multiple cloning simulations. J Chem Phys 2024; 160:164310. [PMID: 38661201 DOI: 10.1063/5.0203683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/02/2024] [Indexed: 04/26/2024] Open
Abstract
We present the result of our calculations of ultrafast electron diffraction (UED) for cyclobutanone excited into the S2 electronic state, which is based on the non-adiabatic dynamics simulations with the Ab Initio Multiple Cloning (AIMC) method with the electronic structure calculated at the SA(3)-CASSCF(12,12)/aug-cc-pVDZ level of theory. The key features in the UED pattern were identified, which can be used to distinguish between the reaction pathways observed in the AIMC dynamics, although there is a significant overlap between representative signals due to the structural similarity of the products. The calculated UED pattern can be compared with the experiment.
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Affiliation(s)
- Dmitry V Makhov
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
- School of Mathematics, University of Bristol, Fry Building, Woodland Road, Bristol BS8 1UG, United Kingdom
| | - Lewis Hutton
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
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4
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Northey T, Kirrander A, Weber PM. Extracting the electronic structure signal from X-ray and electron scattering in the gas phase. JOURNAL OF SYNCHROTRON RADIATION 2024; 31:303-311. [PMID: 38385277 PMCID: PMC10914165 DOI: 10.1107/s1600577524000067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 01/03/2024] [Indexed: 02/23/2024]
Abstract
X-ray and electron scattering from free gas-phase molecules is examined using the independent atom model (IAM) and ab initio electronic structure calculations. The IAM describes the effect of the molecular geometry on the scattering, but does not account for the redistribution of valence electrons due to, for instance, chemical bonding. By examining the total, i.e. energy-integrated, scattering from three molecules, fluoroform (CHF3), 1,3-cyclohexadiene (C6H8) and naphthalene (C10H8), the effect of electron redistribution is found to predominantly reside at small-to-medium values of the momentum transfer (q ≤ 8 Å-1) in the scattering signal, with a maximum percent difference contribution at 2 ≤ q ≤ 3 Å-1. A procedure to determine the molecular geometry from the large-q scattering is demonstrated, making it possible to more clearly identify the deviation of the scattering from the IAM approximation at small and intermediate q and to provide a measure of the effect of valence electronic structure on the scattering signal.
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Affiliation(s)
- Thomas Northey
- Department of Chemistry, Brown University, Providence, RI 02912, USA
| | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Peter M. Weber
- Department of Chemistry, Brown University, Providence, RI 02912, USA
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5
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Champenois EG, List NH, Ware M, Britton M, Bucksbaum PH, Cheng X, Centurion M, Cryan JP, Forbes R, Gabalski I, Hegazy K, Hoffmann MC, Howard AJ, Ji F, Lin MF, Nunes JPF, Shen X, Yang J, Wang X, Martinez TJ, Wolf TJA. Femtosecond Electronic and Hydrogen Structural Dynamics in Ammonia Imaged with Ultrafast Electron Diffraction. PHYSICAL REVIEW LETTERS 2023; 131:143001. [PMID: 37862660 DOI: 10.1103/physrevlett.131.143001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/06/2023] [Accepted: 08/12/2023] [Indexed: 10/22/2023]
Abstract
Directly imaging structural dynamics involving hydrogen atoms by ultrafast diffraction methods is complicated by their low scattering cross sections. Here we demonstrate that megaelectronvolt ultrafast electron diffraction is sufficiently sensitive to follow hydrogen dynamics in isolated molecules. In a study of the photodissociation of gas phase ammonia, we simultaneously observe signatures of the nuclear and corresponding electronic structure changes resulting from the dissociation dynamics in the time-dependent diffraction. Both assignments are confirmed by ab initio simulations of the photochemical dynamics and the resulting diffraction observable. While the temporal resolution of the experiment is insufficient to resolve the dissociation in time, our results represent an important step towards the observation of proton dynamics in real space and time.
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Affiliation(s)
- Elio G Champenois
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Nanna H List
- Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Matthew Ware
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Mathew Britton
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Philip H Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Xinxin Cheng
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Martin Centurion
- Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, Nebraska 68588, USA
| | - James P Cryan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Ruaridh Forbes
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Ian Gabalski
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Kareem Hegazy
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | | | - Andrew J Howard
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Fuhao Ji
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Ming-Fu Lin
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J Pedro F Nunes
- Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, Nebraska 68588, USA
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Jie Yang
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Xijie Wang
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Todd J Martinez
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Thomas J A Wolf
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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6
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Acheson K, Kirrander A. Automatic Clustering of Excited-State Trajectories: Application to Photoexcited Dynamics. J Chem Theory Comput 2023; 19:6126-6138. [PMID: 37703098 PMCID: PMC10536988 DOI: 10.1021/acs.jctc.3c00776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Indexed: 09/14/2023]
Abstract
We introduce automatic clustering as a computationally efficient tool for classifying and interpreting trajectories from simulations of photo-excited dynamics. Trajectories are treated as time-series data, with the features for clustering selected by variance mapping of normalized data. The L2-norm and dynamic time warping are proposed as suitable similarity measures for calculating the distance matrices, and these are clustered using the unsupervised density-based DBSCAN algorithm. The silhouette coefficient and the number of trajectories classified as noise are used as quality measures for the clustering. The ability of clustering to provide rapid overview of large and complex trajectory data sets, and its utility for extracting chemical and physical insight, is demonstrated on trajectories corresponding to the photochemical ring-opening reaction of 1,3-cyclohexadiene, noting that the clustering can be used to generate reduced dimensionality representations in an unbiased manner.
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Affiliation(s)
- Kyle Acheson
- EaStCHEM,
School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K.
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.
| | - Adam Kirrander
- Physical
and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, U.K.
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7
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Bertram L, Weber PM, Kirrander A. Mapping the photochemistry of cyclopentadiene: from theory to ultrafast X-ray scattering. Faraday Discuss 2023; 244:269-293. [PMID: 37132432 DOI: 10.1039/d2fd00176d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The photoinduced ring-conversion reaction when cyclopentadiene (CP) is excited at 5.10 eV is simulated using surface-hopping semiclassical trajectories with XMS(3)-CASPT2(4,4)/cc-pVDZ electronic structure theory. In addition, PBE0/def2-SV(P) is employed for ground state propagation of the trajectories. The dynamics is propagated for 10 ps, mapping both the nonadiabatic short-time dynamics (<300 fs) and the increasingly statistical dynamics on the electronic ground state. The short-time dynamics yields a mixture of hot CP and bicyclo[2.1.0]pentene (BP), with the two products reached via different regions of the same conical intersection seam. On the ground state, we observe slow conversion from BP to CP which is modelled by RRKM theory with a transition state determined using PBE0/def2-TZVP. The CP products are furthermore associated with ground state hydrogen shifts and some H-atom dissociation. Finally, the prospects for detailed experimental mapping using novel ultrafast X-ray scattering experiments are discussed and observables for such experiments are predicted. In particular, we assess the possibility of retrieving electronic states and their populations alongside the structural dynamics.
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Affiliation(s)
- Lauren Bertram
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
| | - Peter M Weber
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Adam Kirrander
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.
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8
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Acheson K, Kirrander A. Robust Inversion of Time-Resolved Data via Forward-Optimization in a Trajectory Basis. J Chem Theory Comput 2023; 19:2721-2734. [PMID: 37129988 DOI: 10.1021/acs.jctc.2c01113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
An inversion method for time-resolved data from ultrafast experiments is introduced, based on forward-optimization in a trajectory basis. The method is applied to experimental data from X-ray scattering of the photochemical ring-opening reaction of 1,3-cyclohexadiene and electron diffraction of the photodissociation of CS2. In each case, inversion yields a model that reproduces the experimental data, identifies the main dynamic motifs, and agrees with independent experimental observations. Notably, the method explicitly accounts for continuity constraints and is robust even for noisy data.
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Affiliation(s)
- Kyle Acheson
- EaStCHEM, School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, United Kingdom
| | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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9
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Gabalski I, Sere M, Acheson K, Allum F, Boutet S, Dixit G, Forbes R, Glownia JM, Goff N, Hegazy K, Howard AJ, Liang M, Minitti MP, Minns RS, Natan A, Peard N, Rasmus WO, Sension RJ, Ware MR, Weber PM, Werby N, Wolf TJA, Kirrander A, Bucksbaum PH. Transient vibration and product formation of photoexcited CS 2 measured by time-resolved x-ray scattering. J Chem Phys 2022; 157:164305. [PMID: 36319419 PMCID: PMC9625835 DOI: 10.1063/5.0113079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/03/2022] [Indexed: 11/14/2022] Open
Abstract
We have observed details of the internal motion and dissociation channels in photoexcited carbon disulfide (CS2) using time-resolved x-ray scattering (TRXS). Photoexcitation of gas-phase CS2 with a 200 nm laser pulse launches oscillatory bending and stretching motion, leading to dissociation of atomic sulfur in under a picosecond. During the first 300 fs following excitation, we observe significant changes in the vibrational frequency as well as some dissociation of the C-S bond, leading to atomic sulfur in the both 1D and 3P states. Beyond 1400 fs, the dissociation is consistent with primarily 3P atomic sulfur dissociation. This channel-resolved measurement of the dissociation time is based on our analysis of the time-windowed dissociation radial velocity distribution, which is measured using the temporal Fourier transform of the TRXS data aided by a Hough transform that extracts the slopes of linear features in an image. The relative strength of the two dissociation channels reflects both their branching ratio and differences in the spread of their dissociation times. Measuring the time-resolved dissociation radial velocity distribution aids the resolution of discrepancies between models for dissociation proposed by prior photoelectron spectroscopy work.
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Affiliation(s)
- Ian Gabalski
- Author to whom correspondence should be addressed:
| | | | - Kyle Acheson
- School of Chemistry, University of Edinburgh, Edinburgh EH8 9YL, United Kingdom
| | | | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Gopal Dixit
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - James M. Glownia
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Nathan Goff
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | | | | | - Mengning Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Michael P. Minitti
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Russell S. Minns
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Adi Natan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Nolan Peard
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Weronika O. Rasmus
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Roseanne J. Sension
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Matthew R. Ware
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Peter M. Weber
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | | | | | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OX1 3QX Oxford, United Kingdom
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10
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Coe JP, Moreno Carrascosa A, Simmermacher M, Kirrander A, Paterson MJ. Efficient Computation of Two-Electron Reduced Density Matrices via Selected Configuration Interaction. J Chem Theory Comput 2022; 18:6690-6699. [PMID: 36198067 PMCID: PMC9648180 DOI: 10.1021/acs.jctc.2c00738] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We create an approach to efficiently calculate two-electron
reduced
density matrices (2-RDMs) using selected configuration interaction
wavefunctions. This is demonstrated using the specific example of
Monte Carlo configuration interaction (MCCI). The computation of the
2-RDMs is accelerated by using ideas from fast implementations of
full configuration interaction (FCI) and recent advances in implementing
the Slater–Condon rules using hardware bitwise operations.
This method enables a comparison of MCCI and truncated CI 2-RDMs with
FCI values for a range of molecules, which includes stretched bonds
and excited states. The accuracy in energies, wavefunctions, and 2-RDMs
is seen to exhibit a similar behavior. We find that MCCI can reach
sufficient accuracy of the 2-RDM using significantly fewer configurations
than truncated CI, particularly for systems with strong multireference
character.
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Affiliation(s)
- Jeremy P Coe
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, EdinburghEH14 4AS, U.K
| | | | - Mats Simmermacher
- EaStCHEM, School of Chemistry, University of Edinburgh, EdinburghEH9 3FJ, U.K
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, EdinburghEH9 3FJ, U.K
| | - Martin J Paterson
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, EdinburghEH14 4AS, U.K
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11
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Yong H, Rouxel JR, Keefer D, Mukamel S. Direct Monitoring of Conical Intersection Passage via Electronic Coherences in Twisted X-Ray Diffraction. PHYSICAL REVIEW LETTERS 2022; 129:103001. [PMID: 36112435 DOI: 10.1103/physrevlett.129.103001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/07/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Quantum coherences in electronic motions play a critical role in determining the pathways and outcomes of virtually all photophysical and photochemical molecular processes. However, the direct observation of electronic coherences in the vicinity of conical intersections remains a formidable challenge. We propose a novel time-resolved twisted x-ray diffraction technique that can directly monitor the electronic coherences created as the molecule passes through a conical intersection. We show that the contribution of electronic populations to this signal is canceled out when using twisted x-ray beams that carry a light orbital angular momentum, providing a direct measurement of transient electronic coherences in gas-phase molecules.
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Affiliation(s)
- Haiwang Yong
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Jérémy R Rouxel
- University Lyon, UJM-Saint-Étienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, Saint-Étienne 42023, France
| | - Daniel Keefer
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
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12
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Montoya-Castillo A, Chen MS, Raj SL, Jung KA, Kjaer KS, Morawietz T, Gaffney KJ, van Driel TB, Markland TE. Optically Induced Anisotropy in Time-Resolved Scattering: Imaging Molecular-Scale Structure and Dynamics in Disordered Media with Experiment and Theory. PHYSICAL REVIEW LETTERS 2022; 129:056001. [PMID: 35960558 DOI: 10.1103/physrevlett.129.056001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Time-resolved scattering experiments enable imaging of materials at the molecular scale with femtosecond time resolution. However, in disordered media they provide access to just one radial dimension thus limiting the study of orientational structure and dynamics. Here we introduce a rigorous and practical theoretical framework for predicting and interpreting experiments combining optically induced anisotropy and time-resolved scattering. Using impulsive nuclear Raman and ultrafast x-ray scattering experiments of chloroform and simulations, we demonstrate that this framework can accurately predict and elucidate both the spatial and temporal features of these experiments.
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Affiliation(s)
| | - Michael S Chen
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Sumana L Raj
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Kenneth A Jung
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Kasper S Kjaer
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Tobias Morawietz
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Kelly J Gaffney
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, USA
| | - Tim B van Driel
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Thomas E Markland
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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13
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Razmus WO, Acheson K, Bucksbaum P, Centurion M, Champenois E, Gabalski I, Hoffman MC, Howard A, Lin MF, Liu Y, Nunes P, Saha S, Shen X, Ware M, Warne EM, Weinacht T, Wilkin K, Yang J, Wolf TJA, Kirrander A, Minns RS, Forbes R. Multichannel photodissociation dynamics in CS 2 studied by ultrafast electron diffraction. Phys Chem Chem Phys 2022; 24:15416-15427. [PMID: 35707953 DOI: 10.1039/d2cp01268e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structural dynamics of photoexcited gas-phase carbon disulfide (CS2) molecules are investigated using ultrafast electron diffraction. The dynamics were triggered by excitation of the optically bright 1B2(1Σu+) state by an ultraviolet femtosecond laser pulse centred at 200 nm. In accordance with previous studies, rapid vibrational motion facilitates a combination of internal conversion and intersystem crossing to lower-lying electronic states. Photodissociation via these electronic manifolds results in the production of CS fragments in the electronic ground state and dissociated singlet and triplet sulphur atoms. The structural dynamics are extracted from the experiment using a trajectory-fitting filtering approach, revealing the main characteristics of the singlet and triplet dissociation pathways. Finally, the effect of the time-resolution on the experimental signal is considered and an outlook to future experiments provided.
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Affiliation(s)
- Weronika O Razmus
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Kyle Acheson
- EaStCHEM, School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK.
| | - Philip Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Martin Centurion
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Elio Champenois
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Ian Gabalski
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Matthias C Hoffman
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
| | - Andrew Howard
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Ming-Fu Lin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
| | - Yusong Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Pedro Nunes
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Sajib Saha
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Matthew Ware
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Emily M Warne
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Thomas Weinacht
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA
| | - Kyle Wilkin
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Jie Yang
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Thomas J A Wolf
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Adam Kirrander
- EaStCHEM, School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK.
| | - Russell S Minns
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Ruaridh Forbes
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
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14
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Donovan RJ, Kirrander A, Lawley KP. Heavy Rydberg and ion-pair states: chemistry, spectroscopy and theory. INT REV PHYS CHEM 2022. [DOI: 10.1080/0144235x.2022.2077024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Robert J. Donovan
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam Kirrander
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Kenneth P. Lawley
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
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15
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Moreno Carrascosa A, Coe JP, Simmermacher M, Paterson MJ, Kirrander A. Towards high-resolution X-ray scattering as a probe of electron correlation. Phys Chem Chem Phys 2022; 24:24542-24552. [DOI: 10.1039/d2cp02933b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We demonstrate that X-ray scattering can be used as a probe of electron–electron correlation.
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Affiliation(s)
- Andrés Moreno Carrascosa
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Jeremy P. Coe
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Mats Simmermacher
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Martin J. Paterson
- Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, UK
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
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16
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Yong H, Moreno Carrascosa A, Ma L, Stankus B, Minitti MP, Kirrander A, Weber PM. Determination of excited state molecular structures from time-resolved gas-phase X-ray scattering. Faraday Discuss 2021; 228:104-122. [PMID: 33595043 DOI: 10.1039/d0fd00118j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a comprehensive investigation of a recently introduced method to determine transient structures of molecules in excited electronic states with sub-ångstrom resolution from time-resolved gas-phase scattering signals. The method, which is examined using time-resolved X-ray scattering data measured on the molecule N-methylmorpholine (NMM) at the Linac Coherent Light Source (LCLS), compares the experimentally measured scattering patterns against the simulated patterns corresponding to a large pool of molecular structures to determine the full set of structural parameters. In addition, we examine the influence of vibrational state distributions and find the effect negligible within the current experimental detection limits, despite that the molecules have a comparatively high internal vibrational energy. The excited state structures determined using three structure pools generated using three different computational methods are in good agreement, demonstrating that the procedure is largely independent of the computational chemistry method employed as long as the pool is sufficiently expansive in the vicinity of the sought structure and dense enough to yield good matches to the experimental patterns.
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Affiliation(s)
- Haiwang Yong
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA.
| | | | - Lingyu Ma
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA.
| | - Brian Stankus
- Department of Chemistry and Biochemistry, Western Connecticut State University, Danbury, Connecticut 06810, USA
| | - Michael P Minitti
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Adam Kirrander
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA. and EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Peter M Weber
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA.
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17
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Moreno Carrascosa A, Yang M, Yong H, Ma L, Kirrander A, Weber PM, Lopata K. Mapping static core-holes and ring-currents with X-ray scattering. Faraday Discuss 2021; 228:60-81. [PMID: 33605956 DOI: 10.1039/d0fd00124d] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Measuring the attosecond movement of electrons in molecules is challenging due to the high temporal and spatial resolutions required. X-ray scattering-based methods are promising, but many questions remain concerning the sensitivity of the scattering signals to changes in density, as well as the means of reconstructing the dynamics from these signals. In this paper, we present simulations of stationary core-holes and electron dynamics following inner-shell ionization of the oxazole molecule. Using a combination of time-dependent density functional theory simulations along with X-ray scattering theory, we demonstrate that the sudden core-hole ionization produces a significant change in the X-ray scattering response and how the electron currents across the molecule should manifest as measurable modulations to the time dependent X-ray scattering signal. This suggests that X-ray scattering is a viable probe for measuring electronic processes at time scales faster than nuclear motion.
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Affiliation(s)
| | - Mengqi Yang
- Department of Chemistry, 232 Choppin Hall, Baton Rouge, Louisiana 70803, USA
| | - Haiwang Yong
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lingyu Ma
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ Edinburgh, UK
| | - Peter M Weber
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Kenneth Lopata
- Department of Chemistry, 232 Choppin Hall, Baton Rouge, Louisiana 70803, USA and Center for Computation and Technology, Louisiana State University, Baton Roug, Louisiana 70803, USA.
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18
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Ho PJ, Fouda AEA, Li K, Doumy G, Young L. Ultraintense, ultrashort pulse X-ray scattering in small molecules. Faraday Discuss 2021; 228:139-160. [PMID: 33576361 DOI: 10.1039/d0fd00106f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We examine X-ray scattering from an isolated organic molecule from the linear to nonlinear absorptive regime. In the nonlinear regime, we explore the importance of both the coherent and incoherent channels and observe the onset of nonlinear behavior as a function of pulse duration and energy. In the linear regime, we test the sensitivity of the scattering signal to molecular bonding and electronic correlation via calculations using the independent atom model (IAM), Hartree-Fock (HF) and density functional theory (DFT). Finally, we describe how coherent X-ray scattering can be used to directly visualize femtosecond charge transfer and dissociation within a single molecule undergoing X-ray multiphoton absorption.
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Affiliation(s)
- Phay J Ho
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
| | - Adam E A Fouda
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
| | - Kai Li
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA. and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gilles Doumy
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
| | - Linda Young
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA. and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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19
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Yong H, Xu X, Ruddock JM, Stankus B, Carrascosa AM, Zotev N, Bellshaw D, Du W, Goff N, Chang Y, Boutet S, Carbajo S, Koglin JE, Liang M, Robinson JS, Kirrander A, Minitti MP, Weber PM. Ultrafast X-ray scattering offers a structural view of excited-state charge transfer. Proc Natl Acad Sci U S A 2021; 118:e2021714118. [PMID: 33947814 PMCID: PMC8126834 DOI: 10.1073/pnas.2021714118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Intramolecular charge transfer and the associated changes in molecular structure in N,N'-dimethylpiperazine are tracked using femtosecond gas-phase X-ray scattering. The molecules are optically excited to the 3p state at 200 nm. Following rapid relaxation to the 3s state, distinct charge-localized and charge-delocalized species related by charge transfer are observed. The experiment determines the molecular structure of the two species, with the redistribution of electron density accounted for by a scattering correction factor. The initially dominant charge-localized state has a weakened carbon-carbon bond and reorients one methyl group compared with the ground state. Subsequent charge transfer to the charge-delocalized state elongates the carbon-carbon bond further, creating an extended 1.634 Å bond, and also reorients the second methyl group. At the same time, the bond lengths between the nitrogen and the ring-carbon atoms contract from an average of 1.505 to 1.465 Å. The experiment determines the overall charge transfer time constant for approaching the equilibrium between charge-localized and charge-delocalized species to 3.0 ps.
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Affiliation(s)
- Haiwang Yong
- Department of Chemistry, Brown University, Providence, RI 02912
| | - Xuan Xu
- Department of Chemistry, Brown University, Providence, RI 02912
| | | | - Brian Stankus
- Department of Chemistry and Biochemistry, Western Connecticut State University, Danbury, CT 06810
| | | | - Nikola Zotev
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
- Center for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Darren Bellshaw
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
- Center for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Wenpeng Du
- Department of Chemistry, Brown University, Providence, RI 02912
| | - Nathan Goff
- Department of Chemistry, Brown University, Providence, RI 02912
| | - Yu Chang
- Department of Chemistry, Brown University, Providence, RI 02912
| | - Sébastien Boutet
- Linac Coherent Light Source, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025
| | - Sergio Carbajo
- Linac Coherent Light Source, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025
| | - Jason E Koglin
- Linac Coherent Light Source, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025
| | - Mengning Liang
- Linac Coherent Light Source, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025
| | - Joseph S Robinson
- Linac Coherent Light Source, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom;
- Center for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Michael P Minitti
- Linac Coherent Light Source, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025
| | - Peter M Weber
- Department of Chemistry, Brown University, Providence, RI 02912;
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20
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Yang J, Zhu X, F Nunes JP, Yu JK, Parrish RM, Wolf TJA, Centurion M, Gühr M, Li R, Liu Y, Moore B, Niebuhr M, Park S, Shen X, Weathersby S, Weinacht T, Martinez TJ, Wang X. Simultaneous observation of nuclear and electronic dynamics by ultrafast electron diffraction. Science 2020; 368:885-889. [PMID: 32439793 DOI: 10.1126/science.abb2235] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/03/2020] [Indexed: 01/02/2023]
Abstract
Simultaneous observation of nuclear and electronic motion is crucial for a complete understanding of molecular dynamics in excited electronic states. It is challenging for a single experiment to independently follow both electronic and nuclear dynamics at the same time. Here we show that ultrafast electron diffraction can be used to simultaneously record both electronic and nuclear dynamics in isolated pyridine molecules, naturally disentangling the two components. Electronic state changes (S1→S0 internal conversion) were reflected by a strong transient signal in small-angle inelastic scattering, and nuclear structural changes (ring puckering) were monitored by large-angle elastic diffraction. Supported by ab initio nonadiabatic molecular dynamics and diffraction simulations, our experiment provides a clear view of the interplay between electronic and nuclear dynamics of the photoexcited pyridine molecule.
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Affiliation(s)
- Jie Yang
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA. .,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Xiaolei Zhu
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA
| | - J Pedro F Nunes
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Jimmy K Yu
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Robert M Parrish
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Thomas J A Wolf
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Martin Centurion
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Markus Gühr
- Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany
| | - Renkai Li
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Yusong Liu
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Bryan Moore
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Mario Niebuhr
- Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany
| | - Suji Park
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Xiaozhe Shen
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | | | - Thomas Weinacht
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
| | - Todd J Martinez
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA. .,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Xijie Wang
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
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21
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Ma L, Yong H, Geiser JD, Moreno Carrascosa A, Goff N, Weber PM. Ultrafast x-ray and electron scattering of free molecules: A comparative evaluation. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:034102. [PMID: 32637459 PMCID: PMC7316516 DOI: 10.1063/4.0000010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/08/2020] [Indexed: 05/09/2023]
Abstract
Resolving gas phase molecular motions with simultaneous spatial and temporal resolution is rapidly coming within the reach of x-ray Free Electron Lasers (XFELs) and Mega-electron-Volt (MeV) electron beams. These two methods enable scattering experiments that have yielded fascinating new results, and while both are important methods for determining transient molecular structures in photochemical reactions, it is important to understand their relative merits. In the present study, we evaluate the respective scattering cross sections of the two methods and simulate their ability to determine excited state molecular structures in light of currently existing XFEL and MeV source parameters. Using the example of optically excited N-methyl morpholine and simulating the scattering patterns with shot noise, we find that the currently achievable signals are superior with x-ray scattering for equal samples and on a per-shot basis and that x-ray scattering requires fewer detected signal counts for an equal fidelity structure determination. Importantly, within the independent atom model, excellent structure determinations can be achieved for scattering vectors only to about 5 Å-1, leaving larger scattering vector ranges for investigating vibrational motions and wavepackets. Electron scattering has a comparatively higher sensitivity toward hydrogen atoms, which may point to applications where electron scattering is inherently the preferred choice, provided that excellent signals can be achieved at large scattering angles that are currently difficult to access.
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Affiliation(s)
- Lingyu Ma
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA
| | - Haiwang Yong
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA
| | - Joseph D. Geiser
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA
| | | | - Nathan Goff
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA
| | - Peter M. Weber
- Brown University, Department of Chemistry, Providence, Rhode Island 02912, USA
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22
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Observation of the molecular response to light upon photoexcitation. Nat Commun 2020; 11:2157. [PMID: 32358535 PMCID: PMC7195484 DOI: 10.1038/s41467-020-15680-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 03/23/2020] [Indexed: 12/02/2022] Open
Abstract
When a molecule interacts with light, its electrons can absorb energy from the electromagnetic field by rapidly rearranging their positions. This constitutes the first step of photochemical and photophysical processes that include primary events in human vision and photosynthesis. Here, we report the direct measurement of the initial redistribution of electron density when the molecule 1,3-cyclohexadiene (CHD) is optically excited. Our experiments exploit the intense, ultrashort hard x-ray pulses of the Linac Coherent Light Source (LCLS) to map the change in electron density using ultrafast x-ray scattering. The nature of the excited electronic state is identified with excellent spatial resolution and in good agreement with theoretical predictions. The excited state electron density distributions are thus amenable to direct experimental observation. Photoabsorption is a fundamental process that leads to changes in the electron density in matter. Here, the authors show a direct measurement of the distribution of electron density when a cyclohexadine molecule is excited by pulsed UV radiation and probed by a time delayed X-ray pulse generated at LCLS.
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23
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Zotev N, Moreno Carrascosa A, Simmermacher M, Kirrander A. Excited Electronic States in Total Isotropic Scattering from Molecules. J Chem Theory Comput 2020; 16:2594-2605. [DOI: 10.1021/acs.jctc.9b00670] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nikola Zotev
- EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Andrés Moreno Carrascosa
- EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Mats Simmermacher
- EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Adam Kirrander
- EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, U.K
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24
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Genoni A. On the use of the Obara–Saika recurrence relations for the calculation of structure factors in quantum crystallography. ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 2020; 76:172-179. [DOI: 10.1107/s205327332000042x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/14/2020] [Indexed: 11/10/2022]
Abstract
Modern methods of quantum crystallography are techniques firmly rooted in quantum chemistry and, as in many quantum chemical strategies, electron densities are expressed as two-centre expansions that involve basis functions centred on atomic nuclei. Therefore, the computation of the necessary structure factors requires the evaluation of Fourier transform integrals of basis function products. Since these functions are usually Cartesian Gaussians, in this communication it is shown that the Fourier integrals can be efficiently calculated by exploiting an extension of the Obara–Saika recurrence formulas, which are successfully used by quantum chemists in the computation of molecular integrals. Implementation and future perspectives of the technique are also discussed.
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25
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Grabowsky S, Genoni A, Thomas SP, Jayatilaka D. The Advent of Quantum Crystallography: Form and Structure Factors from Quantum Mechanics for Advanced Structure Refinement and Wavefunction Fitting. 21ST CENTURY CHALLENGES IN CHEMICAL CRYSTALLOGRAPHY II 2020. [DOI: 10.1007/430_2020_62] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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26
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Simmermacher M, Moreno Carrascosa A, E. Henriksen N, B. Møller K, Kirrander A. Theory of ultrafast x-ray scattering by molecules in the gas phase. J Chem Phys 2019; 151:174302. [DOI: 10.1063/1.5110040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mats Simmermacher
- EaStCHEM, School of Chemistry, University of Edinburgh, EH9 3FJ Edinburgh, United Kingdom
| | | | - Niels E. Henriksen
- Department of Chemistry, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Klaus B. Møller
- Department of Chemistry, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, EH9 3FJ Edinburgh, United Kingdom
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27
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Pápai M, Rozgonyi T, Penfold TJ, Nielsen MM, Møller KB. Simulation of ultrafast excited-state dynamics and elastic x-ray scattering by quantum wavepacket dynamics. J Chem Phys 2019; 151:104307. [DOI: 10.1063/1.5115204] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Mátyás Pápai
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
| | - Tamás Rozgonyi
- Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O. Box 286, H-1519 Budapest, Hungary
| | - Thomas J. Penfold
- Chemistry - School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Martin M. Nielsen
- Department of Physics, Technical University of Denmark, Fysikvej 307, DK-2800 Kongens Lyngby, Denmark
| | - Klaus B. Møller
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kongens Lyngby, Denmark
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28
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Yong H, Ruddock JM, Stankus B, Ma L, Du W, Goff N, Chang Y, Zotev N, Bellshaw D, Boutet S, Carbajo S, Koglin JE, Liang M, Robinson JS, Kirrander A, Minitti MP, Weber PM. Scattering off molecules far from equilibrium. J Chem Phys 2019; 151:084301. [PMID: 31470697 DOI: 10.1063/1.5111979] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pump-probe gas phase X-ray scattering experiments, enabled by the development of X-ray free electron lasers, have advanced to reveal scattering patterns of molecules far from their equilibrium geometry. While dynamic displacements reflecting the motion of wavepackets can probe deeply into the reaction dynamics, in many systems, the thermal excitation embedded in the molecules upon optical excitation and energy randomization can create systems that encompass structures far from the ground state geometry. For polyatomic molecular systems, large amplitude vibrational motions are associated with anharmonicity and shifts of interatomic distances, making analytical solutions using traditional harmonic approximations inapplicable. More generally, the interatomic distances in a polyatomic molecule are not independent and the traditional equations commonly used to interpret the data may give unphysical results. Here, we introduce a novel method based on molecular dynamic trajectories and illustrate it on two examples of hot, vibrating molecules at thermal equilibrium. When excited at 200 nm, 1,3-cyclohexadiene (CHD) relaxes on a subpicosecond time scale back to the reactant molecule, the dominant pathway, and to various forms of 1,3,5-hexatriene (HT). With internal energies of about 6 eV, the energy thermalizes quickly, leading to structure distributions that deviate significantly from their vibrationless equilibrium. The experimental and theoretical results are in excellent agreement and reveal that a significant contribution to the scattering signal arises from transition state structures near the inversion barrier of CHD. In HT, our analysis clarifies that previous inconsistent structural parameters determined by electron diffraction were artifacts that might have resulted from the use of inapplicable analytical equations.
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Affiliation(s)
- Haiwang Yong
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Jennifer M Ruddock
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Brian Stankus
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lingyu Ma
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Wenpeng Du
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Nathan Goff
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Yu Chang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Nikola Zotev
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Darren Bellshaw
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Sergio Carbajo
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Jason E Koglin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Mengning Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Joseph S Robinson
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Adam Kirrander
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - Michael P Minitti
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Peter M Weber
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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Northey T, Kirrander A. Ab Initio Fragment Method for Calculating Molecular X-ray Diffraction. J Phys Chem A 2019; 123:3395-3406. [PMID: 30892904 DOI: 10.1021/acs.jpca.9b00621] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A fragment-based approach for the prediction of elastic X-ray scattering is presented. The total diffraction pattern is assembled from anisotropic form factors calculated for individual molecular fragments, optionally including corrections for pairwise interactions between fragments. The approach is evaluated against full ab initio scattering calculations in the peptide diphenylalanine, and the optimal selection of fragments is examined in the ethanol molecule. The approach is found to improve significantly on the independent atom model while remaining conceptually simple and computationally efficient. It is expected to be particularly useful for macromolecules with repeated subunits, such as peptides, proteins, DNA, or RNA and other polymers, where it is straightforward to define appropriate fragments.
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Affiliation(s)
- Thomas Northey
- EaStCHEM, School of Chemistry , University of Edinburgh , David Brewster Road , Edinburgh EH9 3FJ , United Kingdom
| | - Adam Kirrander
- EaStCHEM, School of Chemistry , University of Edinburgh , David Brewster Road , Edinburgh EH9 3FJ , United Kingdom
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