International workshop on theory for attosecond quantum dynamics (IWTAQD) 14

Jan 15 - Feb 6, 2016

Direction to UEC: English, Japanese
Narita to UEC: English

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

Oleg I. Tolstikhin MIPT
Adiabatic Theory
Jan 18 -Feb 6, 2016
Chiennan Liu Fu-jen catholic U He dynamics under FEL Jan 20 - Feb 4, 2016
Vinh Pham Nguyen Thanh Ho Chi Minh City U of Pedagogy Adiabatic Theory Jan 20 - Feb 4, 2016
Akiyoshi Hishikawa Nagoya U FEL, Molecular dynamics
Jan 26-27, 2016
Toshiyuki Azuma
Laser-Atom dynamics
Jan 26, 2016
Trinh Hoai Vinh RIKEN Attosecond dynamics, Tunneling ionization
Jan 26, 2016
Penju Zhang RIKEN
Laser-Atom dynamics Jan 26, 2016
Lev Olegovich Krainov

Jan 18 -Feb 6, 2016
Lingling Du   
Northwest Normal University,Lanzhou
Tunnelin ionization
Jan 18 -Feb 6, 2016
Yueming Zhou
Huazhong University of Sciecne and Technology, Wuhan
Trilobite structure
Jan 15 - Feb 5
Henning Geiseler U of Tokyo
Photo electron experiment
Jan 26, 2016

Cheng Huang
UEC Molecular dynamics
Jan 15 - Feb 6, 2016
Michio Matsuzawa

Jan 26, 2016
Shinichi Watanabe
UEC Cold atoms Jan 15 - Feb 6, 2016
Toru Morishita UEC
Jan 15 - Feb 6, 2016

Hsumin Huang UEC 3-body break up Jan 15 - Feb 6, 2016
Masataka Ohmi UEC TDSE/Adiabatic theory
Jan 15 - Feb 6, 2016
Bangman Wan
Jan 15 - Feb 6, 2016
Hossain Ahmed
Jan 15 - Feb 6, 2016
Tomotake Yamakoshi UEC Cold atoms Jan 15 - Feb 6, 2016
Shun Ohgoda
UEC TDSE/Static Field Induced States
Jan 15 - Feb 6, 2016
Asuka Hara
UEC Attosec dynamics Jan 15 - Feb 6, 2016

Seminar Program

Jan 26  (Tue) 2016@
Place: Bldg. East 6, Rm. 803


10:00-10:30 Andrey I. Dnestryan and Oleg I. Tolstikhin (MIPT)
"Integral equation approach to the weak-field asymptotic theory of tunneling ionization"
The weak-field asymptotic theory of tunneling (WFAT) ionization is rederived on the basis of the integral equation approach, in the spirit of scattering theory. Integral representations of the asymptotic and distortion coefficients appearing in the WFAT expansion for tunneling ionization rate are obtained. These representations are not sensitive to the behavior of the ionizing orbital in the asymptotic region, and hence return reliable results even if the orbital is expanded in Gaussian basis, as is the case in standard quantum chemistry software
packages for electronic structure calculations. This development is expected to greatly simplify the implementation of the WFAT for polyatomic molecules.

10:30-11:00 Lev O. Krainov, Pavel A. Batishchev, and Oleg I. Tolstikhin (MIPT)
"Siegert pseudostate formulation of scattering theory: general three-dimensional case"
The Siegert pseudostate (SPS) formulation of scattering theory is a powerful tool so far developed for spherically symmetric potentials. We generalize SPSs to an arbitrary three-dimensional potential and formulate scattering theory in their terms. After the correct choice of the angular basis the generalization of the SPSs is straightforward. Most of the SPS properties that hold in the spherically symmetric case remain valid for general potentials. SPSs are especially convenient in numerical calculations. We illustrate this by calculating bound states, resonances, and scattering states for anisotropic Yukawa potentials.


11:15-11:45 Lingling Du (North West Normal Univ, China)
"The tunneling ionization and high-order harmonic generation of molecules"
This presentation contains two parts:
Part I  Recent progresses on tunneling ionization of polyatomic molecules
Part II  Ultrashort 38-as pulse generation from the oriented CO molecule driven by few-cycle chirped fs laser in combination with an unipolar pulse.

11:45-12:15 Pengju Zhang (RIKEN)
"Revisit the high-energy tunneled electrons induced by circular/elliptical polarized intense laser field:our recent measurements and comparison with proposed theories"
The photoelectron energy spectra for Xe atom was measured under intense laser field (2.6x10^14W/cm^w) by utilizing the conventional time-of-fight (TOF) system. The high energy tunneled electrons exist as the ellipticity gradually changing from linear to circular, which can be intuitively interpreted as the multiple revisit of the electrons induced at the different instant of the laser cycle.


Akiyoshi Hishikawa (Nagoya U)
"Coincidence momentum imaging of asymmetric Coulomb explosion of CO2 in phase-locked two-color intense laser fields"
Coulomb explosion of CO2, CO2 CO2+ + 2e| CO+ + O+ + 2e|, in phase-locked two-color ultrashort intense laser fields (800 nm and 400 nm, ∼1014 W/cm2) has been investigated by coincidence momentum imaging. The momentum images of the O+ and CO+ fragments show asymmetric distributions along the laser polarization direction depending on the relative phase of the two-color laser fields. The fragment asymmetry becomes most prominent (∼4%) at the relative phases providing the largest asymmetry of the electric field amplitude, with the O+ fragments preferentially ejected to the stronger field side. The mechanism of the asymmetric bond breaking of the two equivalent C-O bonds is discussed in terms of the nuclear dynamics in CO2+ .

14:00-14:30 Henning Geiseler (U of Tokyo)
"The role of the carrier-envelope phase in laser-induced electron diffraction"
The electron rescattering mechanism in intense laser fields has recently drawn interest as a tool for self-imaging of a target molecule with the added benefit of a
temporal resolution on the order of only a few femtoseconds. The basis for this technique is the extraction of scattering cross sections from rescattered
photoelectron momentum distributions, but in actual implementations so far, due to experimental constraints, the focus has mostly been on the angular distribution of the cross section only. In this talk I will introduce the concept of utilizing the carrier-envelope phase of few-cycle driving pulses in order to also map the rescattering momentum, and present our experimental results using this technique to extract complete doubly-differential scattering cross sections.

Yueming Zhou (Huazhong University of Science and Technology, Wuhan, China)
"Strong-field photoelectron holography: two-color fields"
Recently we have demonstrated that the phase of the scattering amplitude can be obtained from the strong-field photoelectron hologram (SFPEH) resulting from the interference of electrons flying directly to the detector after tunneling ionization and those undergoing near-forward rescattering by the parent ion. Here, we will show that with two-color fields, the two components of electron wave packets involved in SFPEH could be manipulated so that the holographic interferences become clearer and appear in a wider range of the momentum space, which enables us to extract the phase of scattering amplitude over a wider range. In addition, the two-color fields could bring out the holography from the direct and back-scattering electrons, enriching the application of the SFPEH in imaging the ultrafast atomic and molecular dynamics.

Vinh Pham Nguyen Thanh (HCMC U of Pedagogy)
"Adiabatic theory of ionization for circularly polarized laser. Application to molecule"
Recently, we have established the adiabatic theory for studying the photomomentum distribution of atom using arbitrarily polarization laser field. In this talk, we present our results for extending this theory to molecular system. We use circular polarization laser field to prevent the electron from recollising with its parent ion. Thus we can eliminate the rescattering part and focus only on the direct ionization part in the photomomentum. The method is illustrated by calculation of photomomentum distribution for 1s and 2p+ state of H2+.


16:00-16:30 Cheng Huang (UEC)
"Adiabatic study of dissociation of H2+ by strong laser fields"
An adiabatic study of dissociation of H2+ by strong laser fields is implemented. Firstly, Siegert states of H2+ at a variety of static electric fields F and internuclear separations R are calculated by solving stationary Schrodinger equation with the method of adiabatic expansion in parabolic coordinates. Secondly, the nuclear wave packet of H2+ by strong laser fields is propagated on these level surfaces consisting of Siegert states. Because the Siegert states eigenvalue is complex, including the energy and ionization rate of the state, our adiabatic calculation includes both dissociation and ionization. As a demonstration, we consider the dissociation and ionization of H2+ on the 2pu and 3dg states, of which the energy surfaces intersect and form a branch point at R=7.9 a.u. and F=0.052 a.u. Our attentions are focused on the nuclear wave packet dynamics of H2+ when it goes through the branch point. The result indicates that the dissociation pathway of nuclear wave packet can be controlled by tuning the pump time and the peak value of the electric field.

Chiennan Liu  (Fu-Jen Catholic U)
"Photoelectron sidebands induced by a chirped laser field for shot-by-shot temporal characterization of FEL pulses"
We theoretically investigate the laser-assisted photoionization of He by an XUV pulse in the presence of a linearly chirped intense laser pulse by solving the time-dependent SchrNodinger equation within the single-active-electron approximation. Analysis based on the time-dependent perturbation theory is also carried out to provide more physical insights. A new scheme is shown to be capable of extracting the arrival time of an XUV FEL pulse relative to an external laser pulse as well as the XUV pulse duration from the photoelectron sidebands resulting from XUV ionization in the presence of a chirped laser pulse. This scheme is independent of the energy fluctuation and the timing jittering of the FEL pulse. Therefore it can be implemented in a noninvasive way to determine the arrival time of FEL pulses on a shot-by-shot basis in time-resolved spectroscopy.


Trinh Hoai Vinh (RIKEN)
"Probing two-electron dynamics of helium in time domain via fluorescence channel"
In this presentation, we report recent progress on theoretically realizing an attosecond pump-probe scheme applied for two-electron system of helium.  A wave package including several resonances  is prepared by two photon-absorption, then probed by another XUV pulse. We calculate the delay dependence of helium ion in the first excited state, separating 2s and 2p channels. It is shown that the signal is related to collective motions of the wave package.



Toru Morishita,UEC