International workshop on theory for attosecond quantum dynamics (IWTAQD) 21



Jun 18-Jul 6, 2019, supported in part by Nagoya U






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Participants (Bldg. E-6, Rms. 525, 527)

Oleg I. Tolstikhin MIPT
 Adiabatic Theory, Tunneling ionization
 Jun 18-Jul 6, 2019
Chiennan Liu Fu-jen catholic U He dynamics under FEL/IR laser fields
 Jun 24-Jul 6, 2019
Akiyoshi Hishikawa Nagoya U FEL, Molecular dynamics, Local chair of the  prenary conference/seminar
 Jun 27-Jun 29, 2019
Mizuho Fushitani
 Nagoya U FEL. Atomic ionization
 Jun 27-Jun 29, 2019
Akitaka Matsuda
 Nagoya U Molecular dynamics
 Jun 27-Jun 29, 2019
Hikaru Fujise
 Nagoya U Molecular dynamics Jun 27-Jun 29, 2019
Takao Fuji
Toyota Tech Inst
 HHG in solids
 Jun 28
Jens Svensmark UEC
 Molecular dynaimcs in intense laser fields
 Jun 18-Jun25, 2019




Michio Matsuzawa
 UEC

Shinichi Watanabe
 UEC Many body physics Jun 18-Jul 6, 2019




Toru Morishita UEC
 Chair
 Jun 18-Jul 6, 2019
 



Hiroka Hasegawa
 Nagoya U Strong Field Experiment Jun 27-Jun 29, 2019
Daimu Ikeya
 Nagoya U Strong Field Experiment Jun 27-Jun 29, 2019
Minami Takahashi,
 Nagoya U Strong Field Experiment Jun 27-Jun 29, 2019
Kentaro Tani,
Nagoya U Strong Field Experiment Jun 27-Jun 29, 2019
Chiaki Kubo Nagoya U Strong Field Experiment Jun 27-Jun 29, 2019
Kasumi Hashigaya
 UNagoya U Strong Field Experiment Jun 27-Jun 29, 2019








Hirokazu Matsui UEC Molecular ionization
 Jun 18-Jul 6, 2019
Yushiro Suzuki UEC Trilobite structure
 Jun 18-Jul 6, 2019




Shota Ito
 UEC Strong Field Physics Jun 18-Jul 6, 2019
Kakeru Furuhata
 UEC
 Strong Field Physics Jun 18-Jul 6, 2019
Yoshiaki Watanabe
 UEC
 Strong Field Physics
 Jun 18-Jul 6, 2019
Motohide Aoki
 UEC Molecular Dynamics
 Jun 18-Jul 6, 2019
Tsukasa Asami
 UEC Molecular Dynamics Jun 18-Jul 6, 2019
Chiaki Oshiro
 UEC Molecular Dynamics Jun 18-Jul 6, 2019



Plenary session/seminar Program (tentative)
Jun 27  (Thr) 2019
Place: Nagoya U

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16:00-18:00 FREE DISCUSSION
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Jun 28  (Fri) 2019
Place: Nagoya U

09:00-09:40   Takao Fuji (Toyota Tech Inst)
"High-harmonic generation in solids driven by sub-cycle mid-infrared pulses"
Abstract:
High-harmonic generation in a crystalline silicon membrane with sub-cycle mid-infrared pulses has been demonstrated. The high harmonic spectra extend to the ultraviolet region, beyond the direct band gap of silicon. The shape of the spectrum strongly depends on the carrier-envelope phase of the sub-cycle input pulse.

09:40-10:10 Hirokazu Matsui, Oleg I. Tolstikhin, Toru Morishita (UEC)
"Effects of nuclear motion and multi electron on tunneling ionization rates of H2 and D2"
Abstract:
We calculate the tunneling ionization rates for H_2 and D_2 in their ground states with Many-Electron Weak Field Asymptotic Theory (ME-WFAT) within the Born-Oppenheimer Approximation (BOA). Higher order corrections to the ME-WFAT are also evaluated by including the dipole coupling to the two lowest excited states of parent ions of H_2^+ and D_2^+. We investigate how the ionization rate is affected by nuclear motion and multi electron interaction, comparing alignment and field dependence of the rates for H_2^+ and D_2^+ and those within the Single-Active-Electron Approximation (SAEA).

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10:10-10:30 FREE DISCUSSION
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10:30-11:10 Mizuho Fushitani (Nagoya U)
"Electron-ion coincidence spectroscopy of Xe intense EUV laser fields"
Abstract:
We have studied nonlinear ionization processes of Xe induced by EUV FEL fields. We introduced an ion detection scheme into a magnetic bottle type photoelectron spectrometer to carry out simultaneous detections of these charged particles. By analyzing electron spectra in coincidence with Xe4+ ions, we identified two-photon formation of Xe 4d double core hole states (DCH) which compete with ultrafast decays of 4d single core hole (SCH) states.

11:10-11:50 Akitaka Matsuda (Nagoya U)
"Recollision-induced multiple ionization process: Coulomb explosion imaging of CS2 in ultrashort intense laser fields"
Abstract:
Three-body Coulomb explosion imaging of CS2 was performed in order to study the multiple ionization mechanism of molecules in ultrashort intense laser fields. A significant peak shift in the total kinetic energy release was observed at laser field intensities between 0.8 and 1.1 PW/cm2 for Coulomb explosion from CS25+ and CS26+ parent ions, which indicate that the multiple ionization process has changed within this narrow intensity range.

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11:50-13:20 LUNCH DISCUSSION
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13:20-14:20 POSTER SESSION
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Hiroka Hasegawa, Hikaru Fujise, Akitaka Matsuda, Akiyoshi Hishikawa (Nagoya U)
"Asymmetric fragmentation of CH4 in phase-locked two-color intense laser fields"
Abstract:
We observed Coulomb explosion processes, CH42+ → CH3+ + H+ and CH42+ → CH2+ + H2+ in phase-locked two-color intense laser fields by measuring the ion-ion coincidence three-dimensional momentum distribution. We will discuss asymmetric fragmentation that depends on the two-color relative phase for these processes.

Daimu Ikeya; Hikaru Fujise; Akitaka Matsuda; Mizuho Fushitani, Akiyoshi Hishikawa (Nagoya U)
"Coincidence measurement of three-dimensional momentum of tunneling electrons and ions from O2 in intense laser fields"
Abstract:
We carried out three-dimensional coincidence momentum imaging of photoelectrons and photoions from O2 in circularly polarized intense laser fields. The molecular-frame angular distributions and the transversal momentum distributions of photoelectrons will be discussed.

Minami Takahashi, Hikaru Fujise, Akiyoshi Hishikawa (Nagoya U)
"Isotope effects in tunneling ionization of molecular hydrogen in intense circularly polarized laser fields"
Abstract:
The angular distributions of the tunneling ionization rates of D2 were measured by using three-dimensional coincidence momentum imaging of dissociative ionization, D_2 -> D^2+ + D + e-. The obtained results will be compared with those obtained for normal H_2 to clarity the role of nuclear motion on the tunneling ionization.

Kentaro Tani, Chiaki Kubo, Kasumi Hashigaya, Akitaka Matsuda, Akiyoshi Hishikawa (Nagoya U)
"Association reaction of C6H14/N2 gas flow system in femtosecond intense laser fields : laser -field intensity dependence study"
Abstract:
The laser-field intensity dependence of the association reaction of C6H14/N2 gas flow system in laser field intensity was studied in order to understand the many-body reaction mechanism in femtosecond intense laser fields. Generation of hydrogen-capped polyynes, C6H2 and C8H2, were identified from the UV absorption spectroscopy of the product. The many-body reaction mechanism will be discussed based on a close comparison between the nonlinear coefficient of the laser-field intensity dependence of the absorbance and that of the unimolecular fragmentation of C6H14 molecule.

Yushiro Suzuki (UEC), Oleg I. Tolstikhin, and Toru Morishita
"Strong Field Photoelectron Holography for Atomic Targets"
In a recent work[1], it is shown that the phase of the scattering amplitude can be extracted from the strong-field photoelectron holography (SFPEH) pattern for atomic targets with screened Coulomb potentials of the form,  V(r)=-exp [-(r⁄a)^2 ]⁄r, where a is the scattering parameter. In this study, we extend the work for another form of potential, V(r)=exp [-(r⁄10)^2 ]∙[(-2)⁄√(0.4^2+r^2 )+10exp{-(((r-3))⁄0.2)^2 }], that supports shape resonances. We show a phase jump in the SFPEH that corresponds to one of the shape resonances in the TDSE calculation. We discuss the feature with the adiabatic theory.
[1] Y. Zhou, O. I. Tolstikhin, and T. Morishita, Phys. Rev. Lett. 116, 173001 (2016).

Hirokazu Matsui (UEC), Oleg I. Tolstikhin, and Toru Morishita
"Effects of nuclear motion and multi electron on tunneling ionization rates of H2 and D2"
We calculate the tunneling ionization rates for H_2 and D_2 in their ground states with Many-Electron Weak Field Asymptotic Theory (ME-WFAT) within the Born-Oppenheimer Approximation (BOA). Higher order corrections to the ME-WFAT are also evaluated by including the dipole coupling to the two lowest excited states of parent ions of H_2^+ and D_2^+. We investigate how the ionization rate is affected by nuclear motion and multi electron interaction, comparing alignment and field dependences of the rates for H_2^+ and D_2^+ and those within the Single-Active-Electron Approximation (SAEA).
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14:20-14:40 FREE DISCUSSION
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14:40-15:20 Danis N. Yangaliev, Vladimir P. Krainov, and Oleg I Tolstikhin (MIPT)
"Quantum theory of radiation by nonstationary systems with application to high-order harmonic generation"
Abstract:
In quantum theory, the description of radiation by a system of charged particles in stationary and nonstationary cases requires different approaches. While radiative processes in stationary systems are covered in textbooks, the emission of radiation by nonstationary systems driven by some external time-dependent forces has not received due attention. In this paper, we develop a quantum theory describing the spectrum of photons emitted by a generic nonstationary system during the action of the external force and show how to implement it in practical calculations. We also discuss the approximation in which the exact quantum formula for the spectrum reduces to the well-known classical formula with the classical dipole moment substituted by the expectation value of the dipole moment calculated quantum mechanically. This approximation amounts to the conjecture commonly used in the theory of high-order harmonic generation (HHG). To illustrate the theory, we apply it to calculating HHG spectrum for a one-dimensional zero-range-potential model. The spectra obtained from the quantum formula and from the conjecture are different and the difference grows with the degree of ionization. This difference is an observable effect predicted by the present theory.

15:20-16:00 Hikaru Fujise (Nagoya U)
"Molecular-frame photoelectron angular distributions (MFPADs) of tunneling electrons from D2 in circularly polarized intense laser fields"
Abstract:
Molecular orbital structures can be read-out by observing the tunneling electron yield in the molecular frame. In this study, we measured the three-dimensional momentum of photoelectrons and ions produced from molecular deuterium (D2) in circularly polarized intense laser fields (800 nm, 40 fs, ~ 10^14 Wcm^-2). The obtained molecular frame photoelectron angular distribution (MFPAD) and its dependence on KER will be discussed.

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16:00-16:20 FREE DISCUSSION
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16:20-17:00 Vinh N. T. Pham, Oleg I. Tolstikhin, Toru Morishita (UEC)
"Images of molecular orbitals in strong-field photoelectron momentum distributions generated by circularly polarized pulses"
Abstract:
Strong-field photoelectron momentum distributions (PEMDs) generated in the ionization of molecules by circularly polarized laser pulses contain valuable information on the structure of the ionizing molecular orbital. In this work, we investigate using the adiabatic theory how this information is imprinted in and can be extracted from such PEMDs. The PEMDs have a donutlike shape. The variation of a PEMD along the donut reproduces the orientation dependence of the ionization rate of the ionizing orbital, and hence reflects its nodal structure and shape. The transverse structure of the PEMD in cross sections of the donut corresponding to orientations of the molecule at which the ionizing orbital has a node in the direction opposite to that of the instantaneous laser field reflects the interplay of two competing ionization channels, which provides additional information on the orbital structure. We illustrate these features by the analysis of PEMDs for three states of different symmetries of the hydrogen molecular ion H2+.

17:00-17:40 Chiennan Liu (Fu-jen Catholic U)
"Real-time monitoring of two-electron dynamics of helium in time domain"
Abstract:
There are few proposals for exploring ultrafast correlated electron motion in helium atoms using attosecond XUV pump–XUV probe schemes , although none of them has been realized in experiments. I will give a progress report regarding our analysis on a potentially feasible scheme using an ionization plus excitation process followed by a fluorescence emission .

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17:40-20:00 FREE DISCUSSION
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Jun 29  (Sat) 2019
Place: Nagoya U

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10:00-16:00 FREE DISCUSSION
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Toru Morishita,UEC