Solution of the many-electron many-photon problem for strong fields: Application to Li- in one- and two-color laser fields

Mercouris, T; Nicolaides, CA

dc.contributor.author	Mercouris, T	en
dc.contributor.author	Nicolaides, CA	en
dc.date.accessioned	2014-03-01T11:44:35Z
dc.date.available	2014-03-01T11:44:35Z
dc.date.issued	2003	en
dc.identifier.issn	1050-2947	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/37025
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-0042477897&partnerID=40&md5=cc606fc58551025eb5a806c7a43e9d3c	en
dc.subject.classification	Optics	en
dc.subject.classification	Physics, Atomic, Molecular & Chemical	en
dc.subject.other	Laser applications	en
dc.subject.other	Lithium	en
dc.subject.other	Negative ions	en
dc.subject.other	Perturbation techniques	en
dc.subject.other	Photons	en
dc.subject.other	Two-color laser fields	en
dc.subject.other	Electronic structure	en
dc.title	Solution of the many-electron many-photon problem for strong fields: Application to Li- in one- and two-color laser fields	en
heal.type	other	en
heal.identifier.secondary	063403	en
heal.language	English	en
heal.publicationDate	2003	en
heal.abstract	The solution of the many-electron many-photon (MEMP) problem for strong fields is facilitated if the corresponding theory entails a computational methodology that combines economy with accuracy and generality, as regards electronic structure and the incorporation of the continuous spectrum. By applying the nonperturbative MEMP theory (MEMPT) to the prototypical Li- S-1 state, where both radial and angular correlations in the initial state and interchannel couplings in the final scattering states cannot be ignored, we computed frequency-dependent widths Gamma(omega) of multiphoton detachment, as well as energy shifts Delta(omega), for intensities 1x10(9)-1x10(11) W/cm(2), using one- as well as two-color fields. Even though the 1s(2)2p P-2(o) threshold is kept energetically closed, its coupling to the open channel 1s(2)2s S-2 cannot be ignored. For the two-color MEMP problem, the present application of the MEMPT provides results for a four-electron system, whereby the self-consistent field, electron correlation, and interchannel coupling are taken into account. The results for (omega, 3omega) laser fields exhibit the recently predicted [Th. Mercouris and C.A. Nicolaides, Phys. Rev. A 63, 013411 (2001)] linear dependence of the rate on cos Phi, where Phi is the phase difference of the two weak fields. Based on this and on lowest-order perturbation theory (LOPT), we obtain a quantity characteristic of the system atom plus fields, which we name the "interference generalized cross section." For the one-color system, comparison is made with our previous conclusions [C.A. Nicolaides and Th. Mercouris, Chem. Phys. Lett. 159, 45 (1989); J. Opt. Soc. Am. B 7, 494 (1990)] and with results from recent calculations of the two- and three-photon detachment rates by Glass [J. Phys. B 31, L667 (1998)], who implemented R-matrix Floquet theory, and by Telnov and Chu [Phys. Rev. A 66, 043417 (2002)], who implemented time-dependent density-functional theory in the Floquet formulation via exterior complex scaling. Similarities as well as discrepancies are observed. Our results for Gamma(omega) and Delta(omega) involve a dense set of values as a function of omega and provide a clear picture of the physics below, at, and above the 3-->2 photon threshold.	en
heal.publisher	AMERICAN PHYSICAL SOC	en
heal.journalName	Physical Review A - Atomic, Molecular, and Optical Physics	en
dc.identifier.isi	ISI:000183915200091	en
dc.identifier.volume	67	en
dc.identifier.issue	6	en
dc.identifier.spage	634031	en
dc.identifier.epage	634038	en