Existence criteria for stabilization from the scaling behaviour of ionization probabilities

We provide a systematic derivation of the scaling behaviour of various quantities and establish in particular the scale invariance of the ionization probability. We discuss the gauge invariance of the scaling properties and the manner in which they can be exploited as consistency check in explicit analytical expressions, in perturbation theory, in the Kramers-Henneberger and Floquet approximation, in upper and lower bound estimates and fully numerical solutions of the time dependent Schroedinger equation. The scaling invariance leads to a differential equation which has to be satisfied by the ionization probability and which yields an alternative criterium for the existence of atomic bound state stabilization.Comment: 12 pages of Latex, one figur

Efeito da aplicação de silício na resistência às condições ambientais em Eucalyptus grandis.

EVINCI. Resumo 029

Solos da região sudeste da Bahia: atualização da legenda de acordo com o Sistema Brasileiro de Classificação de Solos.

bitstream/CNPS/11825/1/solos_sudeste_bahia.pd

Estudo da mesofauna e macrofauna do solo como parâmetro de crescimento em plantios de Araucaria angustifolia.

EVINCI. Resumo 030

Resonant enhancements of high-order harmonic generation

Solving the one-dimensional time-dependent Schr\"odinger equation for simple model potentials, we investigate resonance-enhanced high-order harmonic generation, with emphasis on the physical mechanism of the enhancement. By truncating a long-range potential, we investigate the significance of the long-range tail, the Rydberg series, and the existence of highly excited states for the enhancements in question. We conclude that the channel closings typical of a short-range or zero-range potential are capable of generating essentially the same effects.Comment: 7 pages revtex, 4 figures (ps files

Ionization Probabilities through ultra-intense Fields in the extreme Limit

We continue our investigation concerning the question of whether atomic bound states begin to stabilize in the ultra-intense field limit. The pulses considered are essentially arbitrary, but we distinguish between three situations. First the total classical momentum transfer is non-vanishing, second not both the total classical momentum transfer and the total classical displacement are vanishing together with the requirement that the potential has a finite number of bound states and third both the total classical momentum transfer and the total classical displacement are vanishing. For the first two cases we rigorously prove, that the ionization probability tends to one when the amplitude of the pulse tends to infinity and the pulse shape remains fixed. In the third case the limit is strictly smaller than one. This case is also related to the high frequency limit considered by Gavrila et al.Comment: 16 pages LateX, 2 figure

On the Influence of Pulse Shapes on Ionization Probability

We investigate analytical expressions for the upper and lower bounds for the ionization probability through ultra-intense shortly pulsed laser radiation. We take several different pulse shapes into account, including in particular those with a smooth adiabatic turn-on and turn-off. For all situations for which our bounds are applicable we do not find any evidence for bound-state stabilization.Comment: 21 pages LateX, 10 figure

On the absence of bound-state stabilization through short ultra-intense fields

We address the question of whether atomic bound states begin to stabilize in the short ultra-intense field limit. We provide a general theory of ionization probability and investigate its gauge invariance. For a wide range of potentials we find an upper and lower bound by non-perturbative methods, which clearly exclude the possibility that the ultra intense field might have a stabilizing effect on the atom. For short pulses we find almost complete ionization as the field strength increases.Comment: 34 pages Late

Efecto de aditivos sobre el calor, textura y aceptación del dulce de umbu (Spondias tuberosa, Arr.Cam.) verde.

El dulce de umbu verde presenta elevada sinérisis debido a bajos pH y teor de pectina, lo que reduce la vida util de este producto. El objetivo de este trabajo fue determinar el efecto de la adición de pectina y jarabe de glucosa sobre el color y la textura instrumental, así como verificar la preferencia sensorial entre las formulaciones. Los resultados mostraron que la adición conjunta de pectina y jarabe de glucosa proporciona dulces com textura más firme y de mayor gomosidad, a su vez mantuverieron mejor el color verde amarillento de la pulpa. Los resultados de preferencia mostraron que el produto tuvo un buen índice de aceptabilidad (70%) y no se observaron diferencias significativas entre los productos