Effect of the Rydberg states on the time evolution of nonstationary states below or just above the ionization threshold

Komninos, Y; Nicolaides, CA

dc.contributor.author	Komninos, Y	en
dc.contributor.author	Nicolaides, CA	en
dc.date.accessioned	2014-03-01T01:22:16Z
dc.date.available	2014-03-01T01:22:16Z
dc.date.issued	2005	en
dc.identifier.issn	1050-2947	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16504
dc.subject.classification	Optics	en
dc.subject.classification	Physics, Atomic, Molecular & Chemical	en
dc.subject.other	Quasicontinuum	en
dc.subject.other	Rydberg states	en
dc.subject.other	Short-time dynamics	en
dc.subject.other	Ionization	en
dc.subject.other	Matrix algebra	en
dc.subject.other	Quantum theory	en
dc.subject.other	Atomic physics	en
dc.title	Effect of the Rydberg states on the time evolution of nonstationary states below or just above the ionization threshold	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevA.72.032716	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevA.72.032716	en
heal.identifier.secondary	032716	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	We consider problems of short-time dynamics of a polyelectronic atomic nonstationary state, V, assumed to be formed as a wave packet at t=0. We focus on two cases, for which the role of the quasicontinuum of the upper part of the Rydberg states, with which the V state has nonzero coupling matrix elements, is investigated. In the first case, the position of the V state is just above the ionization threshold, E=0, and so V dissipates into the free electron continuum as an autoionizing state. The question is how the presence of the Rydberg series converging to E=0 affects the time evolution of the autoionizing V. In the second case, the position of V is embedded in the quasicontinuum of the Rydberg series below threshold. The question is whether there are distinct features in the time evolution of this V, although its position is in the discrete part of the energy spectrum. In this case, by focusing on short times and by evaluating analytically certain infinite sums, analogous to Fourier integrations, the following result is obtained: For small times, the V state evolves as an exponentially decaying state. However, in addition to the term describing exponential decay, there is a term, entering with a small coefficient, which describes exponential growth and eventually dominates. It is shown that exponential decay holds for times shorter than the time tp needed by the wave packet to reach the outer classical turning point. For the decay to be physically meaningful, this time must be smaller than the time td which equals the inverse of the half-width in atomic units. We examined a model system of V-Rydberg state interaction based on the Boron S2 spectrum. The results indicate that the effect is observable on the scale of femtoseconds. © 2005 The American Physical Society.	en
heal.publisher	AMERICAN PHYSICAL SOC	en
heal.journalName	Physical Review A - Atomic, Molecular, and Optical Physics	en
dc.identifier.doi	10.1103/PhysRevA.72.032716	en
dc.identifier.isi	ISI:000232228300096	en
dc.identifier.volume	72	en
dc.identifier.issue	3	en