Mathew Britton

All Publications

• Distinguishing the XUV-induced Coulomb explosion dynamics of iodobenzene using covariance analysis JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS Walmsley, T., Allum, F., Harries, J. R., Kumagai, Y., Lim, S., McManus, J., Nagaya, K., Britton, M., Brouard, M., Bucksbaum, P., Fushitani, M., Gabalski, I., Gejo, T., Hockett, P., Howard, A. J., Iwayama, H., Kukk, E., Lam, C., Minns, R. S., Niozu, A., Nishimuro, S., Niskanen, J., Owada, S., Razmus, W. O., Rolles, D., Somper, J., Ueda, K., Unwin, J., Wada, S., Woodhouse, J. L., Forbes, R., Burt, M., Warne, E. M. 2024; 57 (23)

  View details for DOI 10.1088/1361-6455/ad8799

  View details for Web of Science ID 001342250200001

• Time-Resolved Probing of the Iodobenzene C-Band Using XUV-Induced Electron Transfer Dynamics. ACS physical chemistry Au Unwin, J., Razmus, W. O., Allum, F., Harries, J. R., Kumagai, Y., Nagaya, K., Britton, M., Brouard, M., Bucksbaum, P., Fushitani, M., Gabalski, I., Gejo, T., Hockett, P., Howard, A. J., Iwayama, H., Kukk, E., Lam, C. S., McManus, J., Minns, R. S., Niozu, A., Nishimuro, S., Niskanen, J., Owada, S., Pickering, J. D., Rolles, D., Somper, J., Ueda, K., Wada, S. I., Walmsley, T., Woodhouse, J. L., Forbes, R., Burt, M., Warne, E. M. 2024; 4 (6): 620-631

  Abstract

  Time-resolved extreme ultraviolet spectroscopy was used to investigate photodissociation within the iodobenzene C-band. The carbon-iodine bond of iodobenzene was photolyzed at 200 nm, and the ensuing dynamics were probed at 10.3 nm (120 eV) over a 4 ps range. Two product channels were observed and subsequently isolated by using a global fitting method. Their onset times and energetics were assigned to distinct electron transfer dynamics initiated following site-selective ionization of the iodine photoproducts, enabling the electronic states of the phenyl fragments to be identified using a classical over-the-barrier model for electron transfer. In combination with previous theoretical work, this allowed the corresponding neutral photochemistry to be assigned to (1) dissociation via the 7B2, 8A2, and 8B1 states to give ground-state phenyl, Ph(X), and spin-orbit excited iodine and (2) dissociation through the 7A1 and 8B2 states to give excited-state phenyl, Ph(A), and ground-state iodine. The branching ratio was determined to be 87 ± 4% Ph(X) and 13 ± 4% Ph(A). Similarly, the corresponding amount of energy deposited into the internal phenyl modes in these channels was determined to be 44 ± 10 and 65 ± 21%, respectively, and upper bounds to the channel rise times were found to be 114 ± 6 and 310 ± 60 fs.

  View details for DOI 10.1021/acsphyschemau.4c00036

  View details for PubMedID 39634650

  View details for PubMedCentralID PMC11613270

• Carrier-envelope phase-stabilized ultrashort pulses from a gas-filled multi-pass cell APPLIED PHYSICS LETTERS Khatri, D., Truong, T., Lantigua, C., Kincaid, C., Britton, M., Chini, M. 2024; 125 (9)

  View details for DOI 10.1063/5.0216853

  View details for Web of Science ID 001300368200005

• Time-Resolved Probing of the Iodobenzene C-Band Using XUV-Induced Electron Transfer Dynamics ACS PHYSICAL CHEMISTRY AU Unwin, J., Razmus, W. O., Allum, F., Harries, J. R., Kumagai, Y., Nagaya, K., Britton, M., Brouard, M., Bucksbaum, P., Fushitani, M., Gabalski, I., Gejo, T., Hockett, P., Howard, A. J., Iwayama, H., Kukk, E., Lam, C., McManus, J., Minns, R. S., Niozu, A., Nishimuro, S., Niskanen, J., Owada, S., Pickering, J. D., Rolles, D., Somper, J., Ueda, K., Wada, S., Walmsley, T., Woodhouse, J. L., Forbes, R., Burt, M., Warne, E. M. 2024

  View details for DOI 10.1021/acsphyschemau.4c00036

  View details for Web of Science ID 001289123200001

• The Role of Momentum Partitioning in Covariance Ion Imaging Analysis JOURNAL OF PHYSICAL CHEMISTRY A Walmsley, T., McManus, J. W., Kumagai, Y., Nagaya, K., Harries, J., Iwayama, H., Ashfold, M. R., Britton, M., Bucksbaum, P. H., Downes-Ward, B., Driver, T., Heathcote, D., Hockett, P., Howard, A. J., Lee, J. L., Liu, Y., Kukk, E., Milesevic, D., Minns, R. S., Niozu, A., Niskanen, J., Orr-Ewing, A. J., Owada, S., Robertson, P. A., Rolles, D., Rudenko, A., Ueda, K., Unwin, J., Vallance, C., Brouard, M., Burt, M., Allum, F., Forbes, R. 2024

  Abstract

  We present results from a covariance ion imaging study, which employs extensive filtering, on the relationship between fragment momenta to gain deeper insight into photofragmentation dynamics. A new data analysis approach is introduced that considers the momentum partitioning between the fragments of the breakup of a molecular polycation to disentangle concurrent fragmentation channels, which yield the same ion species. We exploit this approach to examine the momentum exchange relationship between the products, which provides direct insight into the dynamics of molecular fragmentation. We apply these techniques to extensively characterize the dissociation of 1-iodopropane and 2-iodopropane dications prepared by site-selective ionization of the iodine atom using extreme ultraviolet intense femtosecond laser pulses with a photon energy of 95 eV. Our assignments are supported by classical simulations, using parameters largely obtained directly from the experimental data.

  View details for DOI 10.1021/acs.jpca.4c00999

  View details for Web of Science ID 001225153300001

  View details for PubMedID 38713032

• Exploring the ultrafast and isomer-dependent photodissociation of iodothiophenes via site-selective ionization. Physical chemistry chemical physics : PCCP Razmus, W. O., Allum, F., Harries, J., Kumagai, Y., Nagaya, K., Bhattacharyya, S., Britton, M., Brouard, M., Bucksbaum, P. H., Cheung, K., Crane, S. W., Fushitani, M., Gabalski, I., Gejo, T., Ghrist, A., Heathcote, D., Hikosaka, Y., Hishikawa, A., Hockett, P., Jones, E., Kukk, E., Iwayama, H., Lam, H. V., McManus, J. W., Milesevic, D., Mikosch, J., Minemoto, S., Niozu, A., Orr-Ewing, A. J., Owada, S., Rolles, D., Rudenko, A., Townsend, D., Ueda, K., Unwin, J., Vallance, C., Venkatachalam, A., Wada, S. I., Walmsley, T., Warne, E. M., Woodhouse, J. L., Burt, M., Ashfold, M. N., Minns, R. S., Forbes, R. 2024

  Abstract

  C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- and 3-iodothiophene is studied using ultrafast time-resolved extreme ultraviolet (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules and eventual I atom products are probed by site-selective ionization at the I 4d edge using intense XUV pulses, which induce multiple charges initially localized to the iodine atom. At C-I separations below the critical distance for charge transfer (CT), charge can redistribute around the molecule leading to Coulomb explosion and charged fragments with high kinetic energy. At greater C-I separations, beyond the critical distance, CT is no longer possible and the measured kinetic energies of the charged iodine atoms report on the neutral dissociation process. The time and momentum resolved measurements allow determination of the timescales and the respective product momentum and kinetic energy distributions for both isomers, which are interpreted in terms of rival 'direct' and 'indirect' dissociation pathways. The measurements are compared with a classical over the barrier model, which reveals that the onset of the indirect dissociation process is delayed by ∼1 ps relative to the direct process. The kinetics of the two processes show no discernible difference between the two parent isomers, but the branching between the direct and indirect dissociation channels and the respective product momentum distributions show isomer dependencies. The greater relative yield of indirect dissociation products from 262 nm photolysis of 3-iodothiophene (cf. 2-iodothiophene) is attributed to the different partial cross-sections for (ring-centred) π∗ ← π and (C-I bond localized) σ∗ ← (n/π) excitation in the respective parent isomers.

  View details for DOI 10.1039/d3cp06079a

  View details for PubMedID 38616653

• Direct momentum imaging of charge transfer following site-selective ionization PHYSICAL REVIEW A Allum, F., Kumagai, Y., Nagaya, K., Harries, J., Iwayama, H., Britton, M., Bucksbaum, P. H., Burt, M., Brouard, M., Downes-Ward, B., Driver, T., Heathcote, D., Hockett, P., Howard, A. J., Lee, J. L., Liu, Y., Kukk, E., McManus, J. W., Milsesevic, D., Niozu, A., Niskanen, J., Orr-Ewing, A. J., Owada, S., Robertson, P. A., Rudenko, A., Ueda, K., Unwin, J., Vallance, C., Walmsley, T., Minns, R. S., Rolles, D., Ashfold, M. R., Forbes, R. 2023; 108 (4)

  View details for DOI 10.1103/PhysRevA.108.043113

  View details for Web of Science ID 001106456200003

• X-ray induced Coulomb explosion imaging of transient excited-state structural rearrangements in CS₂ COMMUNICATIONS PHYSICS Unwin, J., Allum, F., Britton, M., Gabalski, I., Bromberger, H., Brouard, M., Bucksbaum, P. H., Driver, T., Ekanayake, N., Garg, D., Gougoula, E., Heathcote, D., Howard, A. J., Hockett, P., Holland, D. P., Kumar, S., Lam, C., Lee, J. L., Mcmanus, J., Mikosch, J., Milesevic, D., Minns, R. S., Papadopoulou, C. C., Passow, C., Razmus, W. O., Roeder, A., Rouzee, A., Schuurman, M., Simao, A., Stolow, A., Tul-Noor, A., Vallance, C., Walmsley, T., Rolles, D., Erk, B., Burt, M., Forbes, R. 2023; 6 (1)

  View details for DOI 10.1038/s42005-023-01414-7

  View details for Web of Science ID 001095830300001

• Femtosecond Electronic and Hydrogen Structural Dynamics in Ammonia Imaged with Ultrafast Electron Diffraction. Physical review letters Champenois, E. G., List, N. H., Ware, M., Britton, M., Bucksbaum, P. H., Cheng, X., Centurion, M., Cryan, J. P., Forbes, R., Gabalski, I., Hegazy, K., Hoffmann, M. C., Howard, A. J., Ji, F., Lin, M. F., Nunes, J. P., Shen, X., Yang, J., Wang, X., Martinez, T. J., Wolf, T. J. 2023; 131 (14): 143001

  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.

  View details for DOI 10.1103/PhysRevLett.131.143001

  View details for PubMedID 37862660

• Time-Resolved X-ray Photoelectron Spectroscopy: Ultrafast Dynamics in CS2 Probed at the S 2p Edge. The journal of physical chemistry letters Gabalski, I., Allum, F., Seidu, I., Britton, M., Brenner, G., Bromberger, H., Brouard, M., Bucksbaum, P. H., Burt, M., Cryan, J. P., Driver, T., Ekanayake, N., Erk, B., Garg, D., Gougoula, E., Heathcote, D., Hockett, P., Holland, D. M., Howard, A. J., Kumar, S., Lee, J. W., Li, S., McManus, J., Mikosch, J., Milesevic, D., Minns, R. S., Neville, S., Papadopoulou, C. C., Passow, C., Razmus, W. O., Röder, A., Rouzée, A., Simao, A., Unwin, J., Vallance, C., Walmsley, T., Wang, J., Rolles, D., Stolow, A., Schuurman, M. S., Forbes, R. 2023: 7126-7133

  Abstract

  Recent developments in X-ray free-electron lasers have enabled a novel site-selective probe of coupled nuclear and electronic dynamics in photoexcited molecules, time-resolved X-ray photoelectron spectroscopy (TRXPS). We present results from a joint experimental and theoretical TRXPS study of the well-characterized ultraviolet photodissociation of CS2, a prototypical system for understanding non-adiabatic dynamics. These results demonstrate that the sulfur 2p binding energy is sensitive to changes in the nuclear structure following photoexcitation, which ultimately leads to dissociation into CS and S photoproducts. We are able to assign the main X-ray spectroscopic features to the CS and S products via comparison to a first-principles determination of the TRXPS based on ab initio multiple-spawning simulations. Our results demonstrate the use of TRXPS as a local probe of complex ultrafast photodissociation dynamics involving multimodal vibrational coupling, nonradiative transitions between electronic states, and multiple final product channels.

  View details for DOI 10.1021/acs.jpclett.3c01447

  View details for PubMedID 37534743

• Filming enhanced ionization in an ultrafast triatomic slingshot. Communications chemistry Howard, A. J., Britton, M., Streeter, Z. L., Cheng, C., Forbes, R., Reynolds, J. L., Allum, F., McCracken, G. A., Gabalski, I., Lucchese, R. R., McCurdy, C. W., Weinacht, T., Bucksbaum, P. H. 2023; 6 (1): 81

  Abstract

  Filming atomic motion within molecules is an active pursuit of molecular physics and quantum chemistry. A promising method is laser-induced Coulomb Explosion Imaging (CEI) where a laser pulse rapidly ionizes many electrons from a molecule, causing the remaining ions to undergo Coulomb repulsion. The ion momenta are used to reconstruct the molecular geometry which is tracked over time (i.e., filmed) by ionizing at an adjustable delay with respect to the start of interatomic motion. Results are distorted, however, by ultrafast motion during the ionizing pulse. We studied this effect in water and filmed the rapid "slingshot" motion that enhances ionization and distorts CEI results. Our investigation uncovered both the geometry and mechanism of the enhancement which may inform CEI experiments in many other polyatomic molecules.

  View details for DOI 10.1038/s42004-023-00882-w

  View details for PubMedID 37106058

  View details for PubMedCentralID PMC10140156

• Disentangling sequential and concerted fragmentations of molecular polycations with covariant native frame analysis. Physical chemistry chemical physics : PCCP McManus, J. W., Walmsley, T., Nagaya, K., Harries, J. R., Kumagai, Y., Iwayama, H., Ashfold, M. N., Britton, M., Bucksbaum, P. H., Downes-Ward, B., Driver, T., Heathcote, D., Hockett, P., Howard, A. J., Kukk, E., Lee, J. W., Liu, Y., Milesevic, D., Minns, R. S., Niozu, A., Niskanen, J., Orr-Ewing, A. J., Owada, S., Rolles, D., Robertson, P. A., Rudenko, A., Ueda, K., Unwin, J., Vallance, C., Burt, M., Brouard, M., Forbes, R., Allum, F. 2022

  Abstract

  We present results from an experimental ion imaging study into the fragmentation dynamics of 1-iodopropane and 2-iodopropane following interaction with extreme ultraviolet intense femtosecond laser pulses with a photon energy of 95 eV. Using covariance imaging analysis, a range of observed fragmentation pathways of the resulting polycations can be isolated and interrogated in detail at relatively high ion count rates (12 ions shot-1). By incorporating the recently developed native frames analysis approach into the three-dimensional covariance imaging procedure, contributions from three-body concerted and sequential fragmentation mechanisms can be isolated. The angular distribution of the fragment ions is much more complex than in previously reported studies for triatomic polycations, and differs substantially between the two isomeric species. With support of simple simulations of the dissociation channels of interest, detailed physical insights into the fragmentation dynamics are obtained, including how the initial dissociation step in a sequential mechanism influences rovibrational dynamics in the metastable intermediate ion and how signatures of this nuclear motion manifest in the measured signals.

  View details for DOI 10.1039/d2cp03029b

  View details for PubMedID 36106844

• Coherent control of ultrafast extreme ultraviolet transient absorption NATURE PHOTONICS Peng, P., Mi, Y., Lytova, M., Britton, M., Ding, X., Naumov, A., Corkum, P. B., Villeneuve, D. M. 2022; 16 (1): 45-+

  View details for DOI 10.1038/s41566-021-00907-7

  View details for Web of Science ID 000729643100004

• Control of N₂<SUP>+</SUP> air lasing PHYSICAL REVIEW A Britton, M., Lytova, M., Ko, D., Alqasem, A., Peng, P., Villeneuve, D. M., Zhang, C., Arissian, L., Corkum, P. B. 2020; 102 (5)

  View details for DOI 10.1103/PhysRevA.102.053110

  View details for Web of Science ID 000589275600006

• Short- and long-term gain dynamics in N₂<SUP>+</SUP> air lasing PHYSICAL REVIEW A Britton, M., Lytova, M., Laferriere, P., Peng, P., Morales, F., Ko, D., Richter, M., Polynkin, P., Villeneuve, D. M., Zhang, C., Ivanov, M., Spanner, M., Arissian, L., Corkum, P. B. 2019; 100 (1)

  View details for DOI 10.1103/PhysRevA.100.013406

  View details for Web of Science ID 000475495500004

• Testing the Role of Recollision in N_{2}^{+} Air Lasing. Physical review letters Britton, M., Laferrière, P., Ko, D. H., Li, Z., Kong, F., Brown, G., Naumov, A., Zhang, C., Arissian, L., Corkum, P. B. 2018; 120 (13): 133208

  Abstract

  It has been known for many years that during filamentation of femtosecond light pulses in air, gain is observed on the B to X transition in N_{2}^{+}. While the gain mechanism remains unclear, it has been proposed that recollision, a process that is fundamental to much of strong field science, is critical for establishing gain. We probe this hypothesis by directly comparing the influence of the ellipticity of the pump light on gain in air filaments. Then, we decouple filamentation from gain by measuring the gain in a thin gas jet that we also use for high harmonic generation. The latter allows us to compare the dependence of the gain on the ellipticity of the pump with the dependence of the high harmonic signal on the ellipticity of the fundamental. We find that gain and harmonic generation have very different behavior in both filaments and in the jet. In fact, in a jet we even measure gain with circular polarization. Thus, we establish that recollision does not play a significant role in creating the inversion.

  View details for DOI 10.1103/PhysRevLett.120.133208

  View details for PubMedID 29694197

• Energy-selective optical excitation and detection in InAs/InP quantum dot ensembles using a one-dimensional optical microcavity APPLIED PHYSICS LETTERS Gamouras, A., Britton, M., Khairy, M. M., Mathew, R., Dalacu, D., Poole, P., Poitras, D., Williams, R. L., Hall, K. C. 2013; 103 (25)

  View details for DOI 10.1063/1.4852116

  View details for Web of Science ID 000329973800073