Browsing by Author "JIANG, TF"

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ASPECTS RELATED TO QUANTUM STUDIES OF MULTIPHOTON EXCITATION AND DISSOCIATION OF DIATOMIC-MOLECULES
(1994)
JIANG, TF
;
YUAN, JM
;
物理研究所
;
Institute of Physics
We have carried out quantum-mechanical studies of infrared multiphoton excitation and dissociation of diatomic molecules modeled by Morse oscillators. Two different aspects of such processes are investigated: one concerns quantum dynamics near a nonlinear resonance induced by an external field and calculations of the associated quasienergies and quasi-eigen functions; and the other addresses the effects of dipole moment functions on the above-threshold dissociation spectra, obtained by solving the time-dependent Schrodinger equation directly using the momentum-space Fourier-Grid method. (C) 1994 John Wiley & Sons, Inc.
EFFECT OF SURFACE OPTICAL PHONON ON THE SURFACE IMPURITY STATES OF GAAS AND CDS
(1990-08-01)
JIANG, TF
;
CHUU, DS
;
HAN, CS
;
交大名義發表
;
電子物理學系
FINITE MATRIX COMPUTATIONS APPLIED TO THE SCATTERING OF A WAVEPACKET IN THE COULOMB POTENTIAL
(1995-02-28)
PEN, UL
;
JIANG, TF
;
物理研究所
;
Institute of Physics
We develop a finite dimensional matrix method to treat wavepacket propagation in potential scattering problems. The method is useful for general quantum mechanical problems. The scattering dynamics of a minimum uncertainty wavepacket in the Coulomb potential is presented.
HIGH-FREQUENCY STABILIZATION AND HIGH-ORDER HARMONIC-GENERATION OF AN EXCITED MORSE OSCILLATOR UNDER INTENSE FIELDS
(1993-11-01)
JIANG, TF
;
電子物理學系
;
物理研究所
;
Department of Electrophysics
;
Institute of Physics
We study the quantum dynamics of a Morse oscillator under an intense field with three different frequencies: (1) one much higher than the dissociation energy from an excited state, (2) one resonant with the dissociation energy from an excited state, and (3) an intermediate one. The calculations were performed by using the momentum-space Fourier-grid Hamiltonian method. The high-frequency stabilization and harmonic-generation spectra are shown. The laser frequencies discussed are currently experimentally available.
HIGH-ORDER HARMONIC-GENERATION IN ATOMIC-HYDROGEN AT 248-NM - DIPOLE-MOMENT VERSUS ACCELERATION SPECTRUM
(1992-12-01)
JIANG, TF
;
CHU, SI
;
電子物理學系
;
Department of Electrophysics
We present a study of the high-order harmonic-generation (HG) spectra of atomic hydrogen at 248 nm based on the Fourier transform of the expectation values of the induced dipole moment and acceleration. The calculations were performed by extending a fast-Fourier-transformation split-operator technique (in spherical coordinates) to the solution of the time-dependent wave functions in intense laser fields. It is seen that the acceleration form provides a more satisfactory and accurate framework for the study of the photoemission HG spectrum at very intense fields, particularly when ionization becomes appreciable.
HYPERSPHERICAL COORDINATES METHOD IN THE THEORY OF EXCITON-IONIZED DONOR COMPLEX OF SEMICONDUCTORS
(1990-06-01)
JIANG, TF
;
交大名義發表
;
電子物理學系
;
National Chiao Tung University
;
Department of Electrophysics
NONPERTURBATIVE METHODS FOR THE STUDY OF MULTIPHOTON DYNAMICS IN INTENSE PERIODIC AND MULTICOLOR LASER FIELDS
(1991-02-01)
CHU, SI
;
JIANG, TF
;
電子物理學系
;
Department of Electrophysics
We present a brief account of some recently developed generalized Floquet methods (both time-dependent and time-independent) for the nonperturbative treatment of the time-development of wavefunctions or the density matrix operator of quantum systems driven by intense periodic or multi-color (multi-frequency) laser fields. Both the Schrodinger and Liouville equations are considered. We also explore the feasibility of the fast Fourier transformation (FFT) propagation method for the study of Rydberg atom dynamics. We then present a FFT case study of the time propagation of the wavefunction and coarse-grained Wigner density distribution for the problem of microwave-driven multiphoton excitation and ionization of Rydberg hydrogen atoms.
STRONG-FIELD EFFECTS ON THE ONE-DIMENSIONAL HYDROGEN-ATOM IN MOMENTUM SPACE
(1992-10-01)
PEN, UL
;
JIANG, TF
;
電子物理學系
;
Department of Electrophysics
The time evolution of the ground state of a one-dimensional hydrogen atom in the intense laser pulse is studied directly in momentum space. A finite matrix representation of operators is developed to solve nonperturbatively the time-dependent Schrodinger equation. We find that some numerical limitations in coordinate space of above-threshold ionization (ATI) can be overcome, and clear physical interpretations of the numerical data are possible. Both the ATI and harmonic-generation spectra are obtained. The correlations between these two multiphoton phenomena are discussed.
SURFACE OPTICAL PHONON EFFECTS ON SURFACE IMPURITY STATES IN ISOTROPIC SEMICONDUCTORS INP, INAS AND INSB
(1990-09-01)
JIANG, TF
;
CHUU, DS
;
交大名義發表
;
電子物理學系
;
National Chiao Tung University
TIME EVOLUTION AND MULTIPHOTON IONIZATION OF RYDBERG WAVEPACKET IN MICROWAVE FIELDS
(1995-06-30)
JIANG, TF
;
CHU, SI
;
物理研究所
;
Institute of Physics
We present a theoretical study of the time evolution of Rydberg wavepacket, initially localized in radial space and mimicking the classical particle, undergoing microwave multiphoton ionization. The dynamical behavior of the Rydberg wavepacket is found to be different from that of Rydberg atoms initially prepared at given Rydberg eigenstates. It is seen that the Rydberg wavepacket can exhibit collapse and revival behavior in the short time regime. Further, both the microwave ionization rates and the quantum phase space trajectories of the Rydberg wavepackets exhibit qualitatively different behavior in small scaled-frequency (omega(s) (=omega n(0)(3)) << 1.0) and large scaled-frequency (omega(s) greater than or equal to 1.0) regimes.
VECTORIZABLE WAVE-PROPAGATION FORTRAN CODE FOR CALCULATIONS OF MULTIPHOTON DISSOCIATION
(1992-06-01)
TING, JJL
;
YUAN, JM
;
JIANG, TF
;
電子物理學系
;
Department of Electrophysics
A vectorizable FORTRAN code for the ETA10 or other vector machines for numerical calculation of the time-dependent Schrodinger equation is presented. Preliminary results for the multiphoton dissociation of nitrogen oxide are shown. The applied electric field was approximated by a classical sinusoidal wave; both sinusoidal and cosinusoidal wave forms were tested, and the internuclear potential was taken to be a Morse function. Dissociation histories of three types were found.