Douglas G C Garratt

All Publications

• Attosecond impulsive stimulated X-ray Raman scattering in liquid water. Science advances Alexander, O., Egun, F., Rego, L., Gutierrez, A. M., Garratt, D., Cardenes, G. A., Nogueira, J. J., Lee, J. P., Zhao, K., Wang, R. P., Ayuso, D., Barnard, J. C., Beauvarlet, S., Bucksbaum, P. H., Cesar, D., Coffee, R., Duris, J., Frasinski, L. J., Huse, N., Kowalczyk, K. M., Larsen, K. A., Matthews, M., Mukamel, S., O'Neal, J. T., Penfold, T., Thierstein, E., Tisch, J. W., Turner, J. R., Vogwell, J., Driver, T., Berrah, N., Lin, M. F., Dakovski, G. L., Moeller, S. P., Cryan, J. P., Marinelli, A., Picón, A., Marangos, J. P. 2024; 10 (39): eadp0841

  Abstract

  We report the measurement of impulsive stimulated x-ray Raman scattering in neutral liquid water. An attosecond pulse drives the excitations of an electronic wavepacket in water molecules. The process comprises two steps: a transition to core-excited states near the oxygen atoms accompanied by transition to valence-excited states. Thus, the wavepacket is impulsively created at a specific atomic site within a few hundred attoseconds through a nonlinear interaction between the water and the x-ray pulse. We observe this nonlinear signature in an intensity-dependent Stokes Raman sideband at 526 eV. Our measurements are supported by our state-of-the-art calculations based on the polarization response of water dimers in bulk solvation and propagation of attosecond x-ray pulses at liquid density.

  View details for DOI 10.1126/sciadv.adp0841

  View details for PubMedID 39321305

• Attosecond delays in X-ray molecular ionization. Nature Driver, T., Mountney, M., Wang, J., Ortmann, L., Al-Haddad, A., Berrah, N., Bostedt, C., Champenois, E. G., DiMauro, L. F., Duris, J., Garratt, D., Glownia, J. M., Guo, Z., Haxton, D., Isele, E., Ivanov, I., Ji, J., Kamalov, A., Li, S., Lin, M. F., Marangos, J. P., Obaid, R., O'Neal, J. T., Rosenberger, P., Shivaram, N. H., Wang, A. L., Walter, P., Wolf, T. J., Wörner, H. J., Zhang, Z., Bucksbaum, P. H., Kling, M. F., Landsman, A. S., Lucchese, R. R., Emmanouilidou, A., Marinelli, A., Cryan, J. P. 2024; 632 (8026): 762-767

  Abstract

  The photoelectric effect is not truly instantaneous but exhibits attosecond delays that can reveal complex molecular dynamics1-7. Sub-femtosecond-duration light pulses provide the requisite tools to resolve the dynamics of photoionization8-12. Accordingly, the past decade has produced a large volume of work on photoionization delays following single-photon absorption of an extreme ultraviolet photon. However, the measurement of time-resolved core-level photoionization remained out of reach. The required X-ray photon energies needed for core-level photoionization were not available with attosecond tabletop sources. Here we report measurements of the X-ray photoemission delay of core-level electrons, with unexpectedly large delays, ranging up to 700 as in NO near the oxygen K-shell threshold. These measurements exploit attosecond soft X-ray pulses from a free-electron laser to scan across the entire region near the K-shell threshold. Furthermore, we find that the delay spectrum is richly modulated, suggesting several contributions, including transient trapping of the photoelectron owing to shape resonances, collisions with the Auger-Meitner electron that is emitted in the rapid non-radiative relaxation of the molecule and multi-electron scattering effects. The results demonstrate how X-ray attosecond experiments, supported by comprehensive theoretical modelling, can unravel the complex correlated dynamics of core-level photoionization.

  View details for DOI 10.1038/s41586-024-07771-9

  View details for PubMedID 39169246

  View details for PubMedCentralID 7399650

• Attosecond-pump attosecond-probe x-ray spectroscopy of liquid water. Science (New York, N.Y.) Li, S., Lu, L., Bhattacharyya, S., Pearce, C., Li, K., Nienhuis, E. T., Doumy, G., Schaller, R. D., Moeller, S., Lin, M. F., Dakovski, G., Hoffman, D. J., Garratt, D., Larsen, K. A., Koralek, J. D., Hampton, C. Y., Cesar, D., Duris, J., Zhang, Z., Sudar, N., Cryan, J. P., Marinelli, A., Li, X., Inhester, L., Santra, R., Young, L. 2024: eadn6059

  Abstract

  Attosecond-pump/attosecond-probe experiments have long been sought as the most straightforward method to observe electron dynamics in real time. Although numerous successes have been achieved with overlapped near infrared femtosecond and extreme ultraviolet attosecond pulses combined with theory, true attosecond-pump/attosecond-probe experiments have been limited. We used a synchronized attosecond x-ray pulse pair from an x-ray free electron laser to study the electronic response to valence ionization in liquid water via all x-ray attosecond transient absorption spectroscopy (AX-ATAS). Our analysis showed that the AX-ATAS response is confined to the subfemtosecond timescale, eliminating any hydrogen atom motion and demonstrating experimentally that the 1b1 splitting in the x-ray emission spectrum is related to dynamics and is not evidence for two structural motifs in ambient liquid water.

  View details for DOI 10.1126/science.adn6059

  View details for PubMedID 38359104

• Toward ultrafast soft x-ray spectroscopy of organic photovoltaic devices STRUCTURAL DYNAMICS-US Garratt, D., Matthews, M., Marangos, J. 2024; 11 (1): 010901

  Abstract

  Novel ultrafast x-ray sources based on high harmonic generation and at x-ray free electron lasers are opening up new opportunities to resolve complex ultrafast processes in condensed phase systems with exceptional temporal resolution and atomic site specificity. In this perspective, we present techniques for resolving charge localization, transfer, and separation processes in organic semiconductors and organic photovoltaic devices with time-resolved soft x-ray spectroscopy. We review recent results in ultrafast soft x-ray spectroscopy of these systems and discuss routes to overcome the technical challenges in performing time-resolved x-ray experiments on photosensitive materials with poor thermal conductivity and low pump intensity thresholds for nonlinear effects.

  View details for DOI 10.1063/4.0000214

  View details for Web of Science ID 001145844700001

  View details for PubMedID 38250136

  View details for PubMedCentralID PMC10799687

• Observation of recollision-based high-harmonic generation in liquid isopropanol and the role of electron scattering PHYSICAL REVIEW RESEARCH Alexander, O., Barnard, J. T., Larsen, E. W., Avni, T., Jarosch, S., Gregory, A., Parker, S., Galinis, G., Tofful, A., Garratt, D., Matthews, M. R., Marangos, J. P. 2023; 5 (4)

  View details for DOI 10.1103/PhysRevResearch.5.043030

  View details for Web of Science ID 001089285200006

• Optical control of ultrafast structural dynamics in a fluorescent protein. Nature chemistry Hutchison, C. D., Baxter, J. M., Fitzpatrick, A., Dorlhiac, G., Fadini, A., Perrett, S., Maghlaoui, K., Lefevre, S. B., Cordon-Preciado, V., Ferreira, J. L., Chukhutsina, V. U., Garratt, D., Barnard, J., Galinis, G., Glencross, F., Morgan, R. M., Stockton, S., Taylor, B., Yuan, L., Romei, M. G., Lin, C., Marangos, J. P., Schmidt, M., Chatrchyan, V., Buckup, T., Morozov, D., Park, J., Park, S., Eom, I., Kim, M., Jang, D., Choi, H., Hyun, H., Park, G., Nango, E., Tanaka, R., Owada, S., Tono, K., DePonte, D. P., Carbajo, S., Seaberg, M., Aquila, A., Boutet, S., Barty, A., Iwata, S., Boxer, S. G., Groenhof, G., van Thor, J. J. 2023

  Abstract

  The photoisomerization reaction of a fluorescent protein chromophore occurs on the ultrafast timescale. The structural dynamics that result from femtosecond optical excitation have contributions from vibrational and electronic processes and from reaction dynamics that involve the crossing through a conical intersection. The creation and progression of the ultrafast structural dynamics strongly depends on optical and molecular parameters. When using X-ray crystallography as a probe of ultrafast dynamics, the origin of the observed nuclear motions is not known. Now, high-resolution pump-probe X-ray crystallography reveals complex sub-angstrom, ultrafast motions and hydrogen-bonding rearrangements in the active site of a fluorescent protein. However, we demonstrate that the measured motions are not part of the photoisomerization reaction but instead arise from impulsively driven coherent vibrational processes in the electronic ground state. A coherent-control experiment using a two-colour and two-pulse optical excitation strongly amplifies the X-ray crystallographic difference density, while it fully depletes the photoisomerization process. A coherent control mechanism was tested and confirmed the wave packets assignment.

  View details for DOI 10.1038/s41557-023-01275-1

  View details for PubMedID 37563326

• Delivery of stable ultra-thin liquid sheets in vacuum for biochemical spectroscopy FRONTIERS IN MOLECULAR BIOSCIENCES Barnard, J. T., Lee, J. P., Alexander, O., Jarosch, S., Garratt, D., Picciuto, R., Kowalczyk, K., Ferchaud, C., Gregory, A., Matthews, M., Marangos, J. P. 2022; 9: 1044610

  Abstract

  The development of ultra-thin flat liquid sheets capable of running in vacuum has provided an exciting new target for X-ray absorption spectroscopy in the liquid and solution phases. Several methods have become available for delivering in-vacuum sheet jets using different nozzle designs. We compare the sheets produced by two different types of nozzle; a commercially available borosillicate glass chip using microfluidic channels to deliver colliding jets, and an in-house fabricated fan spray nozzle which compresses the liquid on an axis out of a slit to achieve collision conditions. We find in our tests that both nozzles are suitable for use in X-ray absorption spectroscopy with the fan spray nozzle producing thicker but more stable jets than the commercial nozzle. We also provide practical details of how to run these nozzles in vacuum.

  View details for DOI 10.3389/fmolb.2022.1044610

  View details for Web of Science ID 001027339400001

  View details for PubMedID 36452452

  View details for PubMedCentralID PMC9701818

• Direct observation of ultrafast exciton localization in an organic semiconductor with soft X-ray transient absorption spectroscopy NATURE COMMUNICATIONS Garratt, D., Misiekis, L., Wood, D., Larsen, E. W., Matthews, M., Alexander, O., Ye, P., Jarosch, S., Ferchaud, C., Strueber, C., Johnson, A. S., Bakulin, A. A., Penfold, T. J., Marangos, J. P. 2022; 13 (1): 3414

  Abstract

  The localization dynamics of excitons in organic semiconductors influence the efficiency of charge transfer and separation in these materials. Here we apply time-resolved X-ray absorption spectroscopy to track photoinduced dynamics of a paradigmatic crystalline conjugated polymer: poly(3-hexylthiophene) (P3HT) commonly used in solar cell devices. The π→π* transition, the first step of solar energy conversion, is pumped with a 15 fs optical pulse and the dynamics are probed by an attosecond soft X-ray pulse at the carbon K-edge. We observe X-ray spectroscopic signatures of the initially hot excitonic state, indicating that it is delocalized over multiple polymer chains. This undergoes a rapid evolution on a sub 50 fs timescale which can be directly associated with cooling and localization to form either a localized exciton or polaron pair.

  View details for DOI 10.1038/s41467-022-31008-w

  View details for Web of Science ID 000811535600014

  View details for PubMedID 35701418

  View details for PubMedCentralID PMC9198071

• Attosecond coherent electron motion in Auger-Meitner decay. Science (New York, N.Y.) Li, S., Driver, T., Rosenberger, P., Champenois, E. G., Duris, J., Al-Haddad, A., Averbukh, V., Barnard, J. C., Berrah, N., Bostedt, C., Bucksbaum, P. H., Coffee, R. N., DiMauro, L. F., Fang, L., Garratt, D., Gatton, A., Guo, Z., Hartmann, G., Haxton, D., Helml, W., Huang, Z., LaForge, A. C., Kamalov, A., Knurr, J., Lin, M., Lutman, A. A., MacArthur, J. P., Marangos, J. P., Nantel, M., Natan, A., Obaid, R., O'Neal, J. T., Shivaram, N. H., Schori, A., Walter, P., Wang, A. L., Wolf, T. J., Zhang, Z., Kling, M. F., Marinelli, A., Cryan, J. P. 1800: eabj2096

  Abstract

  [Figure: see text].

  View details for DOI 10.1126/science.abj2096

  View details for PubMedID 34990213

• Time-resolved pump-probe spectroscopy with spectral domain ghost imaging. Faraday discussions Li, S., Driver, T., Alexander, O., Cooper, B., Garratt, D., Marinelli, A., Cryan, J. P., Marangos, J. P. 2021

  Abstract

  An atomic-level picture of molecular and bulk processes, such as chemical bonding and charge transfer, necessitates an understanding of the dynamical evolution of these systems. On the ultrafast timescales associated with nuclear and electronic motion, the temporal behaviour of a system is often interrogated in a 'pump-probe' scheme. Here, an initial 'pump' pulse triggers dynamics through photoexcitation, and after a carefully controlled delay a 'probe' pulse initiates projection of the instantaneous state of the evolving system onto an informative measurable quantity, such as electron binding energy. In this paper, we apply spectral ghost imaging to a pump-probe time-resolved experiment at an X-ray free-electron laser (XFEL) facility, where the observable is spectral absorption in the X-ray regime. By exploiting the correlation present in the shot-to-shot fluctuations in the incoming X-ray pulses and measured electron kinetic energies, we show that spectral ghost imaging can be applied to time-resolved pump-probe measurements. In the experiment presented, interpretation of the measurement is simplified because spectral ghost imaging separates the overlapping contributions to the photoelectron spectrum from the pump and probe pulse.

  View details for DOI 10.1039/d0fd00122h

  View details for PubMedID 33625412

• Inner Valence Hole Migration in Isopropanol Alexander, O., Barillot, T., Cooper, B., Driver, T., Garratt, D., Li, S., Marinelli, A., Cryan, J. P., Marangos, J. P., LR25 Collaboration, IEEE IEEE. 2021

  View details for DOI 10.1109/CLEO/Europe-EQEC52157.2021.9542202

  View details for Web of Science ID 000728078300580

• Electronic Population Transfer via Impulsive Stimulated X-Ray Raman Scattering with Attosecond Soft-X-Ray Pulses. Physical review letters O'Neal, J. T., Champenois, E. G., Oberli, S., Obaid, R., Al-Haddad, A., Barnard, J., Berrah, N., Coffee, R., Duris, J., Galinis, G., Garratt, D., Glownia, J. M., Haxton, D., Ho, P., Li, S., Li, X., MacArthur, J., Marangos, J. P., Natan, A., Shivaram, N., Slaughter, D. S., Walter, P., Wandel, S., Young, L., Bostedt, C., Bucksbaum, P. H., Picón, A., Marinelli, A., Cryan, J. P. 2020; 125 (7): 073203

  Abstract

  Free-electron lasers provide a source of x-ray pulses short enough and intense enough to drive nonlinearities in molecular systems. Impulsive interactions driven by these x-ray pulses provide a way to create and probe valence electron motions with high temporal and spatial resolution. Observing these electronic motions is crucial to understand the role of electronic coherence in chemical processes. A simple nonlinear technique for probing electronic motion, impulsive stimulated x-ray Raman scattering (ISXRS), involves a single impulsive interaction to produce a coherent superposition of electronic states. We demonstrate electronic population transfer via ISXRS using broad bandwidth (5.5 eV full width at half maximum) attosecond x-ray pulses produced by the Linac Coherent Light Source. The impulsive excitation is resonantly enhanced by the oxygen 1s→2π^{*} resonance of nitric oxide (NO), and excited state neutral molecules are probed with a time-delayed UV laser pulse.

  View details for DOI 10.1103/PhysRevLett.125.073203

  View details for PubMedID 32857563

• Electronic Population Transfer via Impulsive Stimulated X-Ray Raman Scattering with Attosecond Soft-X-Ray Pulses PHYSICAL REVIEW LETTERS O'Neal, J. T., Champenois, E. G., Oberli, S., Obaid, R., Al-Haddad, A., Barnard, J., Berrah, N., Coffee, R., Duris, J., Galinis, G., Garratt, D., Glownia, J. M., Haxton, D., Ho, P., Li, S., Li, X., MacArthur, J., Marangos, J. P., Natan, A., Shivaram, N., Slaughter, D. S., Walter, P., Wandel, S., Young, L., Bostedt, C., Bucksbaum, P. H., Picon, A., Marinelli, A., Cryan, J. P. 2020; 125 (7)

  View details for DOI 10.1103/PhysRevLett.125.073203

  View details for Web of Science ID 000558086800003

• Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy. Physical chemistry chemical physics : PCCP Driver, T., Li, S., Champenois, E. G., Duris, J., Ratner, D., Lane, T. J., Rosenberger, P., Al-Haddad, A., Averbukh, V., Barnard, T., Berrah, N., Bostedt, C., Bucksbaum, P. H., Coffee, R., DiMauro, L. F., Fang, L., Garratt, D., Gatton, A., Guo, Z., Hartmann, G., Haxton, D., Helml, W., Huang, Z., LaForge, A., Kamalov, A., Kling, M. F., Knurr, J., Lin, M., Lutman, A. A., MacArthur, J. P., Marangos, J. P., Nantel, M., Natan, A., Obaid, R., O'Neal, J. T., Shivaram, N. H., Schori, A., Walter, P., Li Wang, A., Wolf, T. J., Marinelli, A., Cryan, J. P. 2019

  Abstract

  The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray transient absorption spectroscopy, where the X-ray absorption spectrum is measured by scanning the central photon energy and recording the resultant photoproducts. The spectral bandwidth inherent to attosecond pulses is wide compared to the resonant features typically probed, which generally precludes the application of this technique in the attosecond regime. In this paper we propose and demonstrate a new technique to conduct transient absorption spectroscopy with broad bandwidth attosecond pulses with the aid of ghost imaging, recovering sub-bandwidth resolution in photoproduct-based absorption measurements.

  View details for DOI 10.1039/c9cp03951a

  View details for PubMedID 31793561