Imperial College London

DrVitaliAverbukh

Faculty of Natural SciencesDepartment of Physics

Reader in Molecular Physics
 
 
 
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Contact

 

+44 (0)20 7594 7746v.averbukh Website

 
 
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Location

 

209Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

72 results found

Khokhlova M, Bahmanpour L, Bachhawat N, Cooper B, Averbukh Vet al., 2020, Interatomic coulombic decay rate in endohedral complexes, Journal of Physics B: Atomic, Molecular and Optical Physics, Vol: 53, Pages: 184002-184002, ISSN: 0953-4075

Journal article

Driver T, Cooper B, Ayers R, Pipkorn R, Patchkovskii S, Averbukh V, Klug D, Marangos J, Frasinski L, Edelson-Averbukh Met al., Two-dimensional partial covariance mass spectrometry of large molecules based on fragment correlations, Physical Review X, ISSN: 2160-3308

Journal article

Kolorenc P, Averbukh V, 2020, Fano-ADC(2,2) method for electronic decay rates, JOURNAL OF CHEMICAL PHYSICS, Vol: 152, ISSN: 0021-9606

Journal article

Driver T, Li S, Champenois EG, Duris J, Ratner D, Lane TJ, Rosenberger P, Al-Haddad A, Averbukh V, Barnard T, Berrah N, Bostedt C, Bucksbaum PH, Coffee R, DiMauro LF, Fang L, Garratt D, Gatton A, Guo Z, Hartmann G, Haxton D, Helml W, Huang Z, LaForge A, Kamalov A, Kling MF, Knurr J, Lin M-F, Lutman AA, MacArthur JP, Marangos JP, Nantel M, Natan A, Obaid R, O'Neal JT, Shivaram NH, Schori A, Walter P, Wang AL, Wolf TJA, Marinelli A, Cryan JPet al., 2020, Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy, Publisher: ROYAL SOC CHEMISTRY

Working paper

Khokhlova MA, Cooper B, Ueda K, Prince KC, Kolorenc P, Ivanov MY, Averbulch Vet al., 2019, Molecular Auger Interferometry, Physical Review Letters, Vol: 122, ISSN: 0031-9007

We introduce and present a theory of interferometric measurement of a normal Auger decay lifetime in molecules. Molecular Auger interferometry is based on the coherent phase control of Auger dynamics in a two-color (ω/2ω) laser field. We show that, in contrast to atoms, in oriented molecules of certain point groups the relative ω/2ω phase modulates the total ionization yield. A simple analytical formula is derived for the extraction of the lifetimes of Auger-active states from a molecular Auger interferogram, circumventing the need in either high-resolution or attosecond spectroscopy. We demonstrate the principle of the interferometric Auger lifetime measurement using inner-valence decay in CH3F.

Journal article

Ruberti M, Decleva P, Averbukh V, 2018, Full Ab Initio Many-Electron Simulation of Attosecond Molecular Pump-Probe Spectroscopy., J Chem Theory Comput

Here, we present an ab initio approach to full simulation of an attosecond molecular pump-probe experiment. Sequential molecular double ionization by the pump and probe laser pulses with controlled delay is described from first-principles with a full account of the continuum dynamics of the photoelectrons. Many-electron bound-continuum dynamics is simulated using the time-dependent (TD) molecular B-spline algebraic diagrammatic construction (ADC) method. Our calculations give a quantitative prediction about the creation of a coherent superposition of molecular ionic states in the photoionization process and simulate the probe of the ensuing attosecond dynamics by a second ionizing pulse within a single first-principles many-electron framework. We therefore demonstrate the capability to simulate and interpret the results of a prototypical molecular pump-probe experiment of interest in attoscience. As a particular example, we simulate and elucidate the interpretation of a pump-probe experiment in CO2 aimed at measuring strong field-induced hole dynamics via photoionization yields.

Journal article

Averbukh V, Ruberti M, 2018, First-principles Many-electron Dynamics Using the B-spline Algebraic Diagrammatic Construction Approach, Attosecond Molecular Dynamics, Editors: Vrakking, Lepine, Publisher: Royal Society of Chemistry, Pages: 68-102, ISBN: 9781782629955

In this chapter we present a first-principles theoretical and numerical method based on the many-electron algebraic diagrammatic construction [ADC(n)] schemes for electronic excitations, able to describe the correlated multi-electron ionisation dynamics induced in atomic and molecular systems by laser pulses both in the perturbative and non-perturbative regime. Within the ADC(n) framework, electron correlation is described at different levels of approximation depending on the specific ADC method n used within the ADC hierarchy. An accurate representation of the electronic ionisation continuum is achieved by the implementation and computational optimisation of the first- [ADC(1)] and second-order [ADC(2)] schemes in the monocentric B-spline basis set, which makes it possible to describe highly oscillatory discretised continuum wave-functions. The implementation of the time-dependent version of the B-spline ADC method is made by solving the many-electron time-dependent Schrödinger equation via the Arnoldi Lanczos algorithm. As illustrative examples we present applications of this method to the calculations of both static quantities (photoionisation cross sections of noble gas atoms) and dynamical quantities such as the high harmonic generation spectra of Ar and CO2, and the attosecond transient absorption spectrum in laser dressed He atoms.

Book chapter

Yun R, Narevicius E, Averbukh V, 2018, Penning ionization widths by Fano-algebraic diagrammatic construction method, Journal of Chemical Physics, Vol: 148, ISSN: 0021-9606

We present an ab initio theory and computational method for Penning ionization widths. Our method is based on the Fano theory of resonances, algebraic diagrammatic construction (ADC) scheme for many-electron systems, and Stieltjes imaging procedure. It includes an extension of the Fano-ADC scheme [V. Averbukh and L. S. Cederbaum, J. Chem. Phys. 123, 204107 (2005)] to triplet excited states. Penning ionization widths of various He*-H2states are calculated as a function of the distance R between He* and H2. We analyze the asymptotic (large-R) dependences of the Penning widths in the region where the well-established electron transfer mechanism of the decay is suppressed by the multipole- and/or spin-forbidden energy transfer. The R-12and R-8power laws are derived for the asymptotes of the Penning widths of the singlet and triplet excited states of He*(1s2s1,3S), respectively. We show that the electron transfer mechanism dominates Penning ionization of He*(1s2s3S)-H2up until the He*-H2separation is large enough for the radiative decay of He* to become the dominant channel. The same mechanism also dominates the ionization of He*(1s2s1S)-H2when R < 5 Å. We estimate that the regime of energy transfer in the He*-H2Penning ionization cannot be reached by approaching zero collisional temperature. However, the multipole-forbidden energy transfer mechanism can become important for Penning ionization in doped helium droplets.

Journal article

Ruberti M, Decleva P, Averbukh V, 2018, Multi-channel dynamics in high harmonic generation of aligned CO₂: ab initio analysis with time-dependent B-spline algebraic diagrammatic construction, Physical Chemistry Chemical Physics, Vol: 20, Pages: 8311-8325, ISSN: 1463-9076

Here we present a fully ab initio study of the high-order harmonic generation (HHG) spectrum of aligned CO2 molecules. The calculations have been performed by using the molecular time-dependent (TD) B-spline algebraic diagrammatic construction (ADC) method. We quantitatively study how the sub-cycle laser-driven multi-channel dynamics, as reflected in the position of the dynamical minimum in the HHG spectrum, is affected by the full inclusion of both correlation-driven and laser-driven dipole interchannel couplings. We calculate channel-resolved spectral intensities as well as the phase differences between contributions of the different ionization-recombination channels to the total HHG spectrum. Our results show that electron correlation effectively controls the relative contributions of the different channels to the total HHG spectrum, leading to the opening of the new ones (12Πu, 12Σ), previously disregarded for the aligned molecular setup. We conclude that inclusion of many-electron effects into the theoretical interpretation of molecular HHG spectra is essential in order to correctly extract ultrafast electron dynamics using HHG spectroscopy.

Journal article

Cooper B, Girdlestone S, Burovskiy P, Gaydadjiev G, Averbukh V, Knowles PJ, Luk Wet al., 2017, Quantum Chemistry in Dataflow: Density-Fitting MP2., Journal of Chemical Theory and Computation, Vol: 13, Pages: 5265-5272, ISSN: 1549-9618

We demonstrate the use of dataflow technology in the computation of the correlation energy in molecules at the Møller-Plesset perturbation theory (MP2) level. Specifically, we benchmark density fitting (DF)-MP2 for as many as 168 atoms (in valinomycin) and show that speed-ups between 3 and 3.8 times can be achieved when compared to the MOLPRO package run on a single CPU. Acceleration is achieved by offloading the matrix multiplications steps in DF-MP2 to Dataflow Engines (DFEs). We project that the acceleration factor could be as much as 24 with the next generation of DFEs.

Journal article

Neville SP, Averbukh V, Ruberti M, Yun R, Patchkovskii S, Chergui M, Stolow A, Schuurman MSet al., 2016, Excited state X-ray absorption spectroscopy: Probing both electronic and structural dynamics, JOURNAL OF CHEMICAL PHYSICS, Vol: 145, ISSN: 0021-9606

Journal article

Neville SP, Averbukh V, Patchkovskii S, Ruberti M, Yun R, Chergui M, Stolow A, Schuurman MSet al., 2016, Beyond structure: ultrafast X-ray absorption spectroscopy as a probe of non-adiabatic wavepacket dynamics., Faraday Discussions, ISSN: 1364-5498

The excited state non-adiabatic dynamics of polyatomic molecules, leading to the coupling of structural and electronic dynamics, is a fundamentally important yet challenging problem for both experiment and theory. Ongoing developments in ultrafast extreme vacuum ultraviolet (XUV) and soft X-ray sources present new probes of coupled electronic-structural dynamics because of their novel and desirable characteristics. As one example, inner-shell spectroscopy offers localized, atom-specific probes of evolving electronic structure and bonding (via chemical shifts). In this work, we present the first on-the-fly ultrafast X-ray time-resolved absorption spectrum simulations of excited state wavepacket dynamics: photo-excited ethylene. This was achieved by coupling the ab initio multiple spawning (AIMS) method, employing on-the-fly dynamics simulations, with high-level algebraic diagrammatic construction (ADC) X-ray absorption cross-section calculations. Using the excited state dynamics of ethylene as a test case, we assessed the ability of X-ray absorption spectroscopy to project out the electronic character of complex wavepacket dynamics, and evaluated the sensitivity of the calculated spectra to large amplitude nuclear motion. In particular, we demonstrate the pronounced sensitivity of the pre-edge region of the X-ray absorption spectrum to the electronic and structural evolution of the excited-state wavepacket. We conclude that ultrafast time-resolved X-ray absorption spectroscopy may become a powerful tool in the interrogation of excited state non-adiabatic molecular dynamics.

Journal article

Simpson ER, Sanchez-Gonzalez A, Austin DR, Diveki Z, Hutchinson SEE, Siegel T, Ruberti M, Averbukh V, Miseikis L, Strüber CS, Chipperfield L, Marangos JPet al., 2016, Polarisation response of delay dependent absorption modulation in strong field dressed helium atoms probed near threshold, New Journal of Physics, Vol: 18, ISSN: 1367-2630

Wepresent the first measurement of the vectorial response of strongly dressed helium atoms probed by an attosecond pulse train (APT) polarised either parallel or perpendicular to the dressing field polarisation. The transient absorption is probed as a function of delay between the APT and the Linearly polarised 800 nmfield of peak intensity 1.3∗1014 W cm-2. The APT spans the photon energy range 1642 eV, covering the first ionisation energy of helium (24.59 eV). With parallel polarised dressing and probing fields, we observe modulations with periods of one half and one quarter of the dressing field period. When the polarisation of the dressing field is altered from parallel to perpendicular with respect to the APT polarisation we observe a large suppression in the Modulation depth of the above ionisation threshold absorption. In addition to this we present the intensity dependence of the harmonic modulation depth as a function of delay between the dressing and probe fields, with dressing field peak intensities ranging from 2∗1012 to 2∗1014 W cm-2.We compare our experimental results with a full-dimensional solution of the single-atom time-dependent (TD) Schrdinger equation obtained using the recently developed abinitio TDB-spline ADCmethod and find good qualitative agreement for the above threshold harmonics.

Journal article

Kolorenc P, Averbukh V, Feifel R, Eland Jet al., 2016, Collective relaxation processes in atoms, molecules and clusters, Journal of Physics B-Atomic Molecular and Optical Physics, Vol: 49, ISSN: 1361-6455

Electron correlation is an essential driver of a variety of relaxation processes in excited atomic and molecular systems. These are phenomena which often lead to autoionization typically involving two-electron transitions, such as the well-known Auger effect. However, electron correlation can give rise also to higher-order processes characterized by multi-electron transitions. Basic examples include simultaneous two-electron emission upon recombination of an inner-shell vacancy (double Auger decay) or collective decay of two holes with emission of a single electron. First reports of this class of processes date back to the 1960s, but their investigation intensified only recently with the advent of free-electron lasers. High fluxes of high-energy photons induce multiple excitation or ionization of a system on the femtosecond timescale and under such conditions the importance of multi-electron processes increases significantly. We present an overview of experimental and theoretical works on selected multi-electron relaxation phenomena in systems of different complexity, going from double Auger decay in atoms and small molecules to collective interatomic autoionization processes in nanoscale samples.

Journal article

Feifel R, Eland JHD, Squibb RJ, Mucke M, Zagorodskikh S, Linusson P, Tarantelli F, Kolorenc P, Averbukh Vet al., 2016, Ultrafast Molecular Three-Electron Auger Decay, PHYSICAL REVIEW LETTERS, Vol: 116, ISSN: 0031-9007

Journal article

Simpson ER, Sanchez-Gonzalez A, Austin DR, Diveki Z, Hutchinson SEE, Siegel T, Ruberti M, Averbukh V, Miseikis L, Strüber C, Chipperfield L, Marangos JPet al., 2015, The response of a neutral atom to a strong laser field probed by transient absorption near the ionisation threshold

We present transient absorption spectra of an extreme ultraviolet attosecondpulse train in helium dressed by an 800 nm laser field with intensity rangingfrom $2\times10^{12}$ W/cm$^2$ to $2\times10^{14}$ W/cm$^2$. The energy rangeprobed spans 16-42 eV, straddling the first ionisation energy of helium (24.59eV). By changing the relative polarisation of the dressing field with respectto the attosecond pulse train polarisation we observe a large change in themodulation of the absorption reflecting the vectorial response to the dressingfield. With parallel polarized dressing and probing fields, we observesignificant modulations with periods of one half and one quarter of thedressing field period. With perpendicularly polarized dressing and probingfields, the modulations of the harmonics above the ionisation threshold aresignificantly suppressed. A full-dimensionality solution of the single-atomtime-dependent Schr\"odinger equation obtained using the recently developedab-initio time-dependent B-spline ADC method reproduce some of ourobservations.

Working paper

Sanchez-Gonzalez A, Barillot TR, Squibb RJ, Kolorenc P, Agaker M, Averbukh V, Bearpark MJ, Bostedt C, Bozek JD, Bruce S, Montero SC, Coffee RN, Cooper B, Cryan JP, Dong M, Eland JHD, Fang L, Fukuzawa H, Guehr M, Ilchen M, Johnsson AS, Liekhus-S C, Marinelli A, Maxwell T, Motomura K, Mucke M, Natan A, Osipov T, Ostlin C, Pernpointner M, Petrovic VS, Robb MA, Sathe C, Simpson ER, Underwood JG, Vacher M, Walke DJ, Wolf TJA, Zhaunerchyk V, Rubensson J-E, Berrah N, Bucksbaum PH, Ueda K, Feifel R, Frasinski LJ, Marangos JPet al., 2015, Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL, JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, Vol: 48, ISSN: 0953-4075

Journal article

Shagam Y, Klein A, Skomorowski W, Yun R, Averbukh V, Koch CP, Narevicius Eet al., 2015, Molecular hydrogen interacts more strongly when rotationally excited at low temperatures leading to faster reactions, NATURE CHEMISTRY, Vol: 7, Pages: 921-926, ISSN: 1755-4330

Journal article

Schnorr K, Senftleben A, Schmid G, Augustin S, Kurka M, Rudenko A, Foucar L, Broska A, Meyer K, Anielski D, Boll R, Rolles D, Kuebel M, Kling MF, Jiang YH, Mondal S, Tachibana T, Ueda K, Marchenko T, Simon M, Brenner G, Treusch R, Scheit S, Averbukh V, Ullrich J, Pfeifer T, Schroeter CD, Moshammer Ret al., 2015, Time-resolved study of ICD in Ne dimers using FEL radiation, JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, Vol: 204, Pages: 245-256, ISSN: 0368-2048

Journal article

Kolorenc P, Averbukh V, Eland J, Feifel R, Tarantelli Fet al., 2015, Three-electron collective Auger decay in CH3F, 29th International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588

Conference paper

Averbukh VM, Dzhafarova MZ, Bebchuk GB, Avdeeva KSet al., 2015, [The possibility of using tranexamic acid for the treatment of bleeding in otorhinolaryngology]., Vestn Otorinolaringol, Vol: 80, Pages: 67-69, ISSN: 0042-4668

This article is focused on the analysis of the literature publications pertaining to the problem of bleeding in otorhinolaryngology. It reports the epidemiological data on the structure of bleeding and the main methods used to arrest it. Special attention is given to the possibilities of application of tranexamic acid as an effective hemostatic agent not only for systemic but also for topical administration.

Journal article

Cooper B, Kolorenc P, Frasinski LJ, Averbukh V, Marangos JPet al., 2014, Analysis of a measurement scheme for ultrafast hole dynamics by few femtosecond resolution X-ray pump-probe Auger spectroscopy, Faraday Discussions, Vol: 171, Pages: 93-111, ISSN: 1364-5498

Ultrafast hole dynamics created in molecular systems as a result of sudden ionisation is the focus of much attention in the field of attosecond science. Using the molecule glycine we show through ab initio simulations that the dynamics of a hole, arising from ionisation in the inner valence region, evolves with a timescale appropriate to be measured using X-ray pulses from the current generation of SASE free electron lasers. The examined pump–probe scheme uses X-rays with photon energy below the K edge of carbon (275–280 eV) that will ionise from the inner valence region. A second probe X-ray at the same energy can excite an electron from the core to fill the vacancy in the inner-valence region. The dynamics of the inner valence hole can be tracked by measuring the Auger electrons produced by the subsequent refilling of the core hole as a function of pump–probe delay. We consider the feasibility of the experiment and include numerical simulation to support this analysis. We discuss the potential for all X-ray pump-X-ray probe Auger spectroscopy measurements for tracking hole migration.

Journal article

Ruberti M, Averbukh V, Decleva P, 2014, B-spline algebraic diagrammatic construction: Application to photoionization cross-sections and high-order harmonic generation, JOURNAL OF CHEMICAL PHYSICS, Vol: 141, ISSN: 0021-9606

Journal article

Leeuwenburgh J, Cooper B, Averbukh V, Marangos JP, Ivanov Met al., 2014, Reconstruction of correlation-driven electron-hole dynamics by high-harmonic-generation spectroscopy, Physical Review A, Vol: 90, ISSN: 1094-1622

Journal article

Craigie J, Hammad A, Cooper B, Averbukh Vet al., 2014, Rates of exponential decay in systems of discrete energy levels by Stieltjes imaging, JOURNAL OF CHEMICAL PHYSICS, Vol: 141, ISSN: 0021-9606

Journal article

Ruberti M, Yun R, Gokhberg K, Kopelke S, Cederbaum LS, Tarantelli F, Averbukh Vet al., 2014, Total photoionization cross-sections of excited electronic states by the algebraic diagrammatic construction-Stieltjes-Lanczos method, JOURNAL OF CHEMICAL PHYSICS, Vol: 140, ISSN: 0021-9606

Journal article

Ruberti M, Yun R, Gokhberg K, Kopelke S, Cederbaum LS, Tarantelli F, Averbukh Vet al., 2013, Total molecular photoionization cross-sections by algebraic diagrammatic construction-Stieltjes-Lanczos method: Benchmark calculations, JOURNAL OF CHEMICAL PHYSICS, Vol: 139, ISSN: 0021-9606

Journal article

Leeuwenburgh J, Cooper B, Averbukh V, Marangos JP, Ivanov Met al., 2013, High-Order Harmonic Generation Spectroscopy of Correlation-Driven Electron Hole Dynamics., Physical Review Letters, Vol: 111

We show how high-order harmonic generation spectroscopy can be used to follow correlation-driven electron hole dynamics with attosecond time resolution. The technique is applicable both to normal Auger transitions and to electron hole migration processes that do not lead to secondary electron emission. We theoretically simulate the proposed spectroscopy for M_{4,5}NN Auger decay in Kr and for correlation-driven inner-valence hole dynamics in trans-butadiene and propanal.

Journal article

Schnorr K, Senftleben A, Kurka M, Rudenko A, Foucar L, Schmid G, Broska A, Pfeifer T, Meyer K, Anielski D, Boll R, Rolles D, Kuebel M, Kling MF, Jiang YH, Mondal S, Tachibana T, Ueda K, Marchenko T, Simon M, Brenner G, Treusch R, Scheit S, Averbukh V, Ullrich J, Schroeter CD, Moshammer Ret al., 2013, Time-Resolved Measurement of Interatomic Coulombic Decay in Ne-2, PHYSICAL REVIEW LETTERS, Vol: 111, ISSN: 0031-9007

Journal article

Cooper B, Averbukh V, 2013, Single-photon laser-enabled auger spectroscopy for measuring attosecond electron-hole dynamics., Physical Review Letters, Vol: 111, ISSN: 0031-9007

We propose and simulate a new type of attosecond time-resolved spectroscopy of electron-hole dynamics, applicable particularly to ultrafast hole migration. Attosecond ionization in the inner-valence region is followed by a vacuum ultraviolet probe inducing single-photon laser-enabled Auger decay, a one-photon-two-electron transition filling the inner-valence vacancy. The double ionization probability as a function of the attosecond pump-vacuum ultraviolet probe delay captures efficiently the ultrafast inner-valence hole dynamics. Detailed ab initio calculations are presented for inner-valence hole migration in glycine.

Journal article

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