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Generalized Floquet theoretical formulation of time‐dependent density functional theory for many‐electron systems in multicolor laser fields
Author(s) -
Telnov Dmitry A.,
Chu ShihI
Publication year - 1998
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1998)69:3<305::aid-qua9>3.0.co;2-z
Subject(s) - floquet theory , time dependent density functional theory , hamiltonian (control theory) , ionization , density functional theory , atomic orbital , physics , quantum mechanics , electron , eigenvalues and eigenvectors , atomic physics , chemistry , mathematics , ion , mathematical optimization , nonlinear system
We generalize the Floquet formulation of the time‐dependent density functional theory (TDDFT) [Telnov and Chu, Chem. Phys. Lett. 264 , 466 (1997)] to the case of many‐electron systems in multicolor or polychromatic time‐dependent fields. It is shown that the time‐dependent Kohn–Sham equations can be transformed into an equivalent time‐independent infinite‐dimensional Floquet Hamiltonian eigenvalue problem. For the case of bound‐free transitions, we introduce the notion of complex density and present a non‐Hermitian many‐mode Floquet formulation of TDDFT. A procedure is presented for the determination of the complex quasi‐energies and the calculation of the total and partial ionization rates from individual electron orbitals. The theory is illustrated by a case study of multiphoton ionization of He atoms in the presence of an intense 248 nm laser field and its third harmonic. Novel intensity‐ and phase‐dependent behavior of multiphoton processes in two‐color fields is reported. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 69: 305–315, 1998