Alexei N. Grum-Grzhimailo

General properties of the RABBITT at parity mixing conditions Open

Maria M. Popova, Sergey Yudin, Alexei N. Grum-Grzhimailo, Elena V. Gryzlova · 2025

Parity mixing in photoionization, i.e. when emitted electrons have different parities but the same energy, causes interference observable only in angle-resolved measurements. The interference typically manifests as a symmetry violation in …

Dichroic Electron Emission Patterns from Oriented Helium Ions Open

Niclas Wieland, Klaus Bartschat, Filippa Dudda, R. Wagner, Philipp Schmidt , et al. · 2025

We report a joint experimental and theoretical study using a combination of polarization-controlled free-electron-laser (FEL) and near-infra\-red (NIR) pulses in a synchronized two-color photo\-ionization scheme. Excited He$^+$ ions, creat…

Role of intermediate resonances in attosecond photoelectron interferometry in neon Open

Matteo Moioli, Maria M. Popova, Kathryn R. Hamilton, Dominik Ertel, David Busto , et al. · 2025

Attosecond photoelectron interferometry based on the combination of an attosecond pulse train and a synchronized infrared field is a fundamental technique for the temporal characterization of attosecond waveforms and for the investigation …

Circular dichroism in multiphoton ionization of resonantly excited helium ions near channel closing Open

R. Wagner, Markus Ilchen, Nicolas Douguet, Philipp Schmidt, Niclas Wieland , et al. · 2024

The Advantages of Polarization Control in RABBITT Open

Maria M. Popova, S. N. Yudin, Alexei N. Grum-Grzhimailo, Elena V. Gryzlova · 2024

The RABBITT setup is theoretically studied for various combinations of XUV and IR field components polarization: 'linear+linear', `linear+circular' with crossed propagation directions, and `circular+circular' with parallel propagation dire…

Vector parameters in atomic ionization by twisted light: polarization of electron and residual ion Open

Maksim D. Kiselev, Elena V. Gryzlova, Alexei N. Grum-Grzhimailo · 2023

The electron and ion properties observed in a photoionization inherit a symmetry properties of both a target and a radiation. Introducing a symmetry breaking in a photoionization process one can expect to observe a noticeable variation of …

On Phase and Amplitude Extraction in Bichromatic Ionization: A Proposal Open

Maria M. Popova, Alexei N. Grum-Grzhimailo, Elena V. Gryzlova · 2023

In the paper we propose a method for characterizing VUV pulse(s) in a bichromatic ionization setup. The scheme is based on s-shell ionization by joint action of circularly polarized fundamental harmonic and linearly polarized second one. T…

Angular distribution of photoelectrons generated in atomic ionization by twisted radiation Open

Maksim D. Kiselev, Elena V. Gryzlova, Alexei N. Grum-Grzhimailo · 2023

Until recently, theoretical and experimental studies of photoelectron angular distributions (PADs) including non-dipole effects in atomic photo\-ionization have been performed mainly for the conventional plane-wave radiation. One can expec…

Spectroscopic Peculiarities at Ionization of Excited 2p5(2PJf)3s[K]0,1,2 States of Ne: Cooper Minima and Autoionizing Resonances Open

Maria M. Popova, Maksim D. Kiselev, S. M. Burkov, Elena V. Gryzlova, Alexei N. Grum-Grzhimailo · 2022

An extensive study of photoionization from neon excited states was performed. The R-matrix approach was applied to calculate a photoionization cross-section from the metastable 2p5(2PJf)3s[K]0,2 and dipole-allowed 2p5(2PJf)3s[K]1 states. T…

Influence of an atomic resonance on the coherent control of the photoionization process Open

Elena V. Gryzlova, Paolo Carpeggiani, Maria M. Popova, Maksim D. Kiselev, Nicolas Douguet , et al. · 2022

In coherent control schemes, pathways connecting an initial and a final state can be independently controlled by manipulating the complex amplitudes of their transition matrix elements. For paths characterized by the absorption of multiple…

Evolution of the ionic polarization in multiple sequential ionization: general equations and an illustrative example Open

Elena V. Gryzlova, Alexei N. Grum-Grzhimailo, Maksim D. Kiselev, Maria M. Popova · 2022

The modern Free-Electron-Lasers generate a highly intense polarized radiation which initiate a sequence of ionization and decay events. Their probability depends on the polarization of each state as function of time. Its complete accountin…

An experimental and theoretical study of the Kr 3d correlation satellites Open

Maksim D. Kiselev, Maximilian Reinhardt, Minna Patanen, A. Kivimäki, Ivan Powis , et al. · 2022

The Kr 3d correlation satellites have been studied experimentally by using plane polarized synchrotron radiation to record polarization dependent photoelectron spectra (PES), and theoretically by employing the R-matrix method to calculate …

Mechanisms of 1s Double-Core-Hole Excitation and Decay in Neon Open

Maksim D. Kiselev, Elena V. Gryzlova, S. M. Burkov, Oleg Zatsarinny, Alexei N. Grum-Grzhimailo · 2021

The formation and decay of double-core-hole (DCH) states of the neon ion irradiated by an intense electromagnetic x-ray field are studied theoretically. In the present research DCH formation is the result of sequential absorption of two ph…

Oleg Zatsarinny (1953–2021): Memories by His Colleagues Open

Klaus Bartschat, Charlotte Froese Fischer, Alexei N. Grum-Grzhimailo · 2021

A collection of short stories about Oleg Ivanovich Zatsarinny (1953–2021) to whom this Special Issue of Atoms is dedicated.

Complex Attosecond Waveform Synthesis at FEL FERMI Open

Praveen Kumar Maroju, Cesare Grazioli, Michele Di Fraia, Matteo Moioli, Dominik Ertel , et al. · 2021

Free-electron lasers (FELs) can produce radiation in the short wavelength range extending from the extreme ultraviolet (XUV) to the X-rays with a few to a few tens of femtoseconds pulse duration. These facilities have enabled significant b…

A Tribute to Oleg Zatsarinny (1953–2021): His Life in Science Open

Klaus Bartschat, Charlotte Froese Fischer, Alexei N. Grum-Grzhimailo · 2021

Oleg Ivanovich Zatsarinny (Figure 1) was born in the city of Uzhgorod, Ukraine, on 4 November 1953 [...]

Intense quasi-monochromatic resonant harmonic generation in the multiphoton ionization regime Open

Mangaljit Singh, M. A. Fareed, V. V. Strelkov, Alexei N. Grum-Grzhimailo, A. I. Magunov , et al. · 2021

Resonant high-order harmonics, which result in quasi-monochromatic extreme ultraviolet light with coherent intensity enhancement involving autoionizing resonances, have been demonstrated from laser-ablated plumes in the tunnel-ionization r…

Symmetry Violation in Bichromatic Ionization by a Free-Electron Laser: Photoelectron Angular Distribution and Spin Polarization Open

Maria M. Popova, Elena V. Gryzlova, Maksim D. Kiselev, Alexei N. Grum-Grzhimailo · 2021

A fundamental phenomenon of coherent control is investigated theoretically using the example of neon photoionization by the bichromatic field of a free-electron laser. A system exposed to coherent fields with commensurable frequencies lose…

Analysis of two-color photoelectron spectroscopy for attosecond metrology at seeded free-electron lasers Open

Praveen Kumar Maroju, Cesare Grazioli, Michele Di Fraia, Matteo Moioli, Dominik Ertel , et al. · 2021

The generation of attosecond pulse trains at free-electron lasers opens new opportunities in ultrafast science, as it gives access, for the first time, to reproducible, programmable, extreme ultraviolet (XUV) waveforms with high intensity.…

Near-threshold two-photon double ionization of Kr in the vacuum ultraviolet Open

Lazaros Varvarezos, S. Düsterer, Maksim D. Kiselev, Rebecca Boll, Cédric Bomme , et al. · 2021

We report angle-resolved measurements on photoelectrons emitted upon near-threshold two-photon double ionization (TPDI) of Kr irradiated by free-electron laser (FEL) pulses. These photoelectron angular distributions (PADs) are compared wit…

Mapping Resonance Structures in Transient Core-Ionized Atoms Open

Tommaso Mazza, Markus Ilchen, Maksim D. Kiselev, Elena V. Gryzlova, T. Baumann , et al. · 2020

The nature of transient electronic states created by photoabsorption critically determines the dynamics of the subsequently evolving system. Here, we investigate K-shell photoionized atomic neon by absorbing a second photon within the Auge…

Multiple Sequential Ionization of Valence n = 4 Shell of Krypton by Intense Femtosecond XUV Pulses Open

Elena V. Gryzlova, Maksim D. Kiselev, Maria M. Popova, Anton A. Zubekhin, G. Sansone , et al. · 2020

Sequential photoionization of krypton by intense extreme ultraviolet femtosecond pulses is studied theoretically for the photon energies below the 3d excitation threshold. This regime with energetically forbidden Auger decay is characteriz…

Attosecond pulse shaping using a seeded free-electron laser Open

Praveen Kumar Maroju, Cesare Grazioli, Michele Di Fraia, Matteo Moioli, Dominik Ertel , et al. · 2020

On the effect of cascade transitions after electron-impact excitation of Zn by spin-polarized electrons Open

Klaus Bartschat, y Zatsarinny, Christopher J. Bostock, Dmitry V. Fursa, Igor Bray , et al. · 2020

Synopsis We investigate the possible effect of cascade transitions from the (4s5p) 3 P 0,1,2 states to the (4s5s) 3 S 1 state of Zn. Our calculations suggest that the excitation cross sections and the polarization of the cascade radiation …

Attosecond delays in photoionization studied with coherent-controlled FEL Open

Daehyun You, Kiyoshi Ueda, Oyunbileg Tugs, Yuki Orimo, Takeshi Sato , et al. · 2020

Synopsis When an electron is ejected from an atom after absorption of a photon, the photoelectron wave packet has an extremely short group delay between the photon absorption and the electron emission. This interval, called the Eisenbud-Wi…

Coherent control of the photoelectron angular distribution in ionization of neon by a circularly polarized bichromatic field in the resonance region Open

Elena V. Gryzlova, Maria M. Popova, Alexei N. Grum-Grzhimailo, Ekaterina I. Staroselskaya, Nicolas Douguet , et al. · 2019

Coherent control of the photoelectron angular distribution (PAD) in ionization by a bichromatic circularly polarized field is theoretically studied in neon in the photon energy range 16-20 eV. The breakdown of the PAD axial symmetry with r…

Complete Characterization of Phase and Amplitude of Bichromatic Extreme Ultraviolet Light Open

Michele Di Fraia, Oksana Plekan, Carlo Callegari, Kevin C. Prince, L. Giannessi , et al. · 2019

Intense, mutually coherent beams of multiharmonic extreme ultraviolet light can now be created using seeded free-electron lasers, and the phase difference between harmonics can be tuned with attosecond accuracy. However, the absolute value…

Two-color XUV plus near-IR multiphoton near-threshold ionization of the helium ion by circularly polarized light in the vicinity of the resonance Open

Alexei N. Grum-Grzhimailo, Nicolas Douguet, Michael Meyer, Klaus Bartschat · 2019

Two-color XUV plus near-IR multiphoton ionization of the helium ion by circularly polarized light is studied in the vicinity of the 3p resonance. Combining the analysis of results obtained by solving the time-dependent Schrödinger equation…

A new quantum clock for measuring photoemission delay times Open

Daehyun You, Kiyoshi Ueda, Elena V. Gryzlova, Alexei N. Grum-Grzhimailo, Maria M. Popova , et al. · 2019

The age of attosecond physics was ushered in by the invention of methods for probing phenomena on a time scale less than femtoseconds [F. Krausz, M. Ivanov, Rev. Mod. Phys. 81, 163 (2009)]. In photoemission, the Eisenbud-Wigner-Smith (EWS)…

Roadmap on photonic, electronic and atomic collision physics: I. Light–matter interaction Open

Kiyoshi Ueda, Emma Sokell, S. Schippers, F. Aumayr, H. R. Sadeghpour , et al. · 2019

We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. In Roadmap I, we focus on the light–matter interaction. In this area, studies of ultrafast …

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