International workshop on theory for attosecond quantum dynamics (IWTAQD) 12

Jan 19 -Feb 10, 2015


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 19 -Feb 7, 2015
Chiennan Liu	Fu-jen catholic U	He dynamics under FEL	Feb 2 -Feb 10, 2015
Vinh Pham Nguyen Thanh	Ho Chi Minh City U of Pedagogy	Adiabatic Theory	Feb 26-Feb , 2015
Akiyohi Hishikawa	Nagoya U	FEL, Molecular dynamics	Feb 3-4, 2015
Akitaka Matsura	Nagoya U	Molecular dynamics	Feb 2-4, 2015
Tomoyori Endo	Nagoya U	Molecular dissociation	Feb 2-4, 2015
Hideo Sekino	Toyohashi U of Tech	Quantum Chemistry	Feb 2-3, 2015
Koji Ando	Kyoto U	Quantum transfer processes in chemical many-body systems	Feb 2-5, 2015
Takeshi Sato	U of Tokyo	Quantum Chemistry	Feb 3, 2015
Yuta Ito	Tohoku U	Electron rescattering	Feb 2-4, 2015
Susumu Kuma	RIKEN	FEL	Feb 3, 2015
Penju Zhang	RIKEN	Intense Laser	Feb 3, 2015
Satoshi Ashihara	IIS, the Univ. of Tokyo	Nano rod	Feb 3, 2015
Michio Matsuzawa	UEC
Shinichi Watanabe	UEC	Cold atoms	Jan 19 -Feb 10, 2015
Toru Morishita	UEC	Chair	Jan 19 -Feb 10, 2015
Hsumin Hoang	UEC	3-body break up	Jan 19 -Feb 10, 2015
Masataka Ohmi	UEC	TDSE	Jan 19 -Feb 10, 2015
Hillary Ssemanda	UEC	Tunneling ionizatoin	Jan 19 -Feb 10, 2015
Tomotake Yamakoshi	UEC	Cold atoms	Jan 19 -Feb 10, 2015
Shun Ohgoda	UEC	Cold atoms	Jan 19 -Feb 10, 2015
Asuka Hara	UEC	Attosec dynamics	Jan 19 -Feb 10, 2015

Seminar Program (tentative)

Feb  3 (Tue) 2015　
Place: Bldg. East 6, Rm. 803

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09:00-09:30  Oleg I Tolstikhin (MIPT)
"`Slow' time discretization: a versatile time propagator for the time-dependent Schroedinger equation"
We present the slow time discretization (STD) method for solving the time-dependent Schr¨odinger equation. The method is an extension of the slow variable discretization method for solving the stationary Schr¨odinger equation (Tolstikhin et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 L389), with time treated as the ‘slow’ variable. It is based on an expansion of the state vector in a discrete variable representation basis, in time, and an adiabatic basis, in Hilbert space. This approach is much more efficient in implementation than a direct solution of the Born–Fock equations. The versatility of the STD time propagator is illustrated through calculations for one-dimensional models of the ionization of hydrogen by an intense laser pulse and resonance charge transfer in proton–hydrogen collisions. The method is shown to perform well in the broad dynamical range considered, from adiabatic to nonadiabatic regimes.

09:30-10:00  Hideo Sekino (Toyohashi U of Tech)
"Quantum Simulation using Multiresolution Multiwavelet (MRMW) basis set"
Conventional basis sets such as Gaussian and plane wave basis functions are constracted intutively focusing on specific purpose and efficient for that purpose. MRMW generated in rather mathematical fashion, though not efficient for some cases, is guranteed to coverge towards complete space result and rigorous within the given threshold for final property.

10:00-10:30 koji Ando (Kyoto U)
"Nuclear and electron wave packet modelling of chemical bond and dynamics"
A simple wave packet (WP) modelling of nuclei and electrons is presented. It employs "floating and breathing" squeezed-state Gaussian WPs, combined in a Hartree product for nuclei and with the perfect-pairing valence-bond spin coupling for electrons. The simplest version deals with zero-point WP broadening dynamics as the central quantum effect when decoherence is anticipated in condensed phase. Nuclear WP with empirical force-field has been applied to a study of hydrogen-bond exchange dynamics in liquid water. A combination of nuclear and electron WPs has been applied to liquid hydrogen, which reproduced the experimental translational diffusion coefficients below 25 K. In cases where the quantum coherence is essential, the WPs are superposed to formulate the propagator via the coherent-state path-integral, whose applicability has been confirmed for a one-dimensional model system and is thus awaiting more applications to realistic systems.

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10:30-11:00 FREE DISCUSSION
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11:00-11:30 Takeshi Sato (U of Tokyo)
 "Implementation of TD-MCSCF methods for atoms"
We have developed time-dependent multiconfiguration self-consistent-field (TD-MCSCF) methods for theoretical investigation of multielectron dynamics in intense laser fields.  This talk describes our recent progress on the implementation of the TD-MCSCF method for three-dimensional many-electron atoms.  The orbital functions are expanded with spherical harmonics, with the radial coordinate discretized with finite-element discrete variable representation.  The electron-electron interaction is accounted for by first solving the Poisson's equation in the spherical harmonic basis, followed by a Legendre-Fourier transform to the  real-space, allowing efficient evaluation of the meanfield operators and electron repulsion integrals.

11:30-12:00 Susumu Kuma (RIKEN)
"Super-radiance at multiple wavelengths from He excited by SCSS EUV free electron laser"
We report the results of simultaneous measurements of super-radiance decays from excited helium atoms at multiple wavelengths. The experiment was performed using extreme ultraviolet (EUV) radiation produced by the free electron laser at the SPring-8 Compact SASE Source (SCSS) test accelerator facility. We observed super-radiant transitions on the 1s3p→1s2s (λ=502 nm), 1s3d→1s2p (λ=668 nm), and 1s3s→1s2p (λ=728 nm) transitions. Several interesting features of the data, some of which appear to contradict with the predictions of the simple two-level super-radiance theory, are discussed.

12:00-12:30 Chiennan Liu
"A proposed soft x-ray coherent control experiment at FERMI"
It has been calculated that the first and third harmonics of FERMI have a fixed phase relationship, a property which has the potential to allow coherent control experiments with FEL radiation. In this short presentation, I will introduce a proposed experiment to measure resonance enhanced two-photon ionization of helium with two phase locked XUV wavelengths, using the first and third harmonics of FEL. If successful, in addition to verification of the fixed phase relative phase between harmonics of FERMI, this will demonstrate the feasibility of such measurements and increase our knowledge of multi-photon ionization.

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12:30-14:30 LUNCH DISCUSSION
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14:30-15:00 Akitaka Matuda (Nagoya U)
"Recollision-induced multiple ionization of CS2 in ultrashort intense laser fields"
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 1 and 2 PW/cm2 for Coulomb explosion from CS25+ and CS26+ parent ions. It is suggested that non-sequential multiple ionization takes place at laser field intensities larger than 2 PW/cm2 where the electron recollision energy exceeds that necessary for direct multiple ionization. On the other hand, when the field intensity is lower than 1 PW/cm2, sequential multiple ionization accompanied by structural deformation of the molecule would take place, leading to the lower kinetic energy release.

15:00-15:30 Pengju Zhang (RIKEN)
"High energy tunneled electron in circularly polarized intense laser field"
The photonelectron spectra of Ar, Kr and Xe atoms irradiated by 800 nm circularly polarized intense laser field were measured by utilizing a conventional time-of-fight apparatus. A high energy tail of the photoelectron spectra was found, by comparing with the adiabatic calculation beyond the ADK model, significant contribution from the sequential multiple ionization was identified. Meanwhile, the discrepancy between the measurement and the adiabatic calculation in the high energy tail area indicates some underlying ionization mechanism.

15:30-15:50 Yuta Ito (Tohoku U)
"Measurement of angle-resolved rescattering photoelectron spectra and extraction of differential scattering cross sections of polyatomic molecules "
Abstract (Click here)

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15:50-16:20 FREE DISCUSSION
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16:20-16:40 Satoshi Ashihara (IIS, the Univ. of Tokyo)
"Optical field emission from resonant gold nanorods driven by femtosecond mid-infrared pulses"
We demonstrate strong-field photoelectron emission from gold nanorods driven by femtosecond mid-infrared optical pulses. The resonant gold nanostructure offers extensive enhancement of the mid-infrared fields, making the photoemission process well into the field-induced tunneling regime. Resonant behavior of the photoelectron yield and the measured photo-electron spectra are discussed.

16:40-17:00 Tomoyuki Endo (Nagoya U)
"Dissociative ionization of NO in two-color intense laser fields"
 Visualization of molecular orbitals has been demonstrated by using high-order harmonics generation and Coulomb explosion in intense laser fields. The approach based on Coulomb explosion or dissociative ionization (DI) utilizes the fact that the spatial anisotropy of laser tunneling ionization rate in molecular frame depends on the shape of molecular orbital. This has a clear advantage that the shape of molecular orbital can be read out from the spatial anisotropy of fragment ion. However, asymmetry in the molecular orbital is not retrieved when a single-color laser pulse having a symmetric electric-field amplitude is employed. In this study, we performed the 3D momentum imaging of N^+ fragment ion produced by DI of NO in two-color laser fields. The obtained momentum images showed a clear asymmetric distribution, demonstrating that the difference between the N and O sides in the molecular orbital can be retrieved by two-color laser fields.

17:00-17:20 Vinh N. T. Pham (HCMC U of Pedagogy)
"Adiabatic theory for molecule in a circular polarization laser field"
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 preliminary 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 photomomemtum.

17:20-17:40 Yueming Zhou (UEC)
"Strong field above threshold ionization by two-color laser pulses"
We apply the adiabatic theory to study the strong field above threshold ionization by the two-color laser pulses. The overall shape of the photoelectron momentum distributions (PEMDs) depend sensitively on the relative phase of the two fields. By changing the relative phase of the two fields, the interference structures of some particular contributions can be enhanced or suppressed, which is very important for experimental observation of the ionization dynamics from the PEMDs. The wavelength dependence of the PEMD is also investigated.

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17:40-20:00 FREE DISCUSSION
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Toru Morishita,UEC