May 28, 1998
The probability that an atom of hydrogen, initially in the 5g(m=4) state, survives a 90-fs pulse of 620 nm wavelength is calculated both by direct integration of the time-dependent Schroedinger equation and by a Floquet calculation. The two methods give virtually identical results. The survival probability calculated for a one-electron model of neon, for the same initial state, pulse duration and wavelength, is in fair quantitative agreement with the experimental data of van Druten et al [Phys. Rev. A 55, 622 (1997)].
Similar papers 1
September 29, 2001
We investigate the stabilization of a hydrogen atom in circularly polarized laser fields. We use a time-dependent, fully three dimensional approach to study the quantum dynamics of the hydrogen atom subject to high intensity, short wavelength laser pulses. We find enhanced survival probability as the field is increased under fixed envelope conditions. We also confirm wavepacket dynamics seen in prior time-dependent computations restricted to two dimensions.
August 21, 2002
Dynamic stabilization of atomic hydrogen against ionization in high-frequency single- and two-color, circularly polarized laser pulses is observed by numerically solving the three-dimensional, time-dependent Schr\"odinger equation. The single-color case is revisited and numerically determined ionization rates are compared with both, exact and approximate high-frequency Floquet rates. The position of the peaks in the photoelectron spectra can be explained with the help of dres...
June 29, 2009
Comparisons of experimental data with numerical predictions of a classical model indicate that an excited hydrogen atom in a pulsed microwave electric field exhibits a nonclassical increase of stability over a relatively wide range of frequencies. I show here that this is due to selective population of long-lived "scarred" states that are associated with the chaotic separatrix band surrounding the principal classical resonance zone in phase space. A quantum explanation is giv...
May 27, 2020
We perform ab initio calculations for the hydrogen atom initially in one of the six circular bound states with the principal quantum numbers n = 2, 3 and 4, irradiated by a short circularly polarized laser pulse of 400 nm. The field propagates in the direction parallel to the z-component of the angular momentum of the atom. We investigate probabilities for the atom to ionize or to get on some bound (excited) state or to remain in the initial state after the end of the laser p...
May 2, 2022
The advent of ultrafast laser science offers the unique opportunity to combine Floquet engineering with extreme time resolution, further pushing the optical control of matter into the petahertz domain. However, what is the shortest driving pulse for which Floquet states can be realised remains an unsolved matter, thus limiting the application of Floquet theory to pulses composed by many optical cycles. Here we ionized Ne atoms with few-femtosecond pulses of selected time dura...
January 18, 2001
Klauder's recent generalization of the harmonic oscillator coherent states [J. Phys. A 29, L293 (1996)] is applicable only in non-degenerate systems, requiring some additional structure if applied to systems with degeneracies. The author suggests how this structure could be added, and applies the complete method to the hydrogen atom problem. To illustrate how a certain degree of freedom in the construction may be exercised, states are constructed which are initially localized...
February 23, 2015
Focusing on the $2\mathrm{p}-1\mathrm{s}$ transition in atomic Hydrogen, we investigate through first order perturbation theory the time evolution of the survival probability of an electron initially taken to be in the excited ($2\mathrm{p}$) state. We examine both the results yielded by the standard dipole approximation for the coupling between the atom and the electromagnetic field -for which we propose a cutoff-independent regularisation- and those yielded by the exact cou...
April 22, 2014
When atoms are exposed to intense laser or microwave pulses ~10% of the atoms are found in Rydberg states subsequent to the pulse, even if it is far more intense than required for static field ionization. The optical spectra of the surviving Li atoms in the presence of a 38 GHz microwave field suggest how atoms survive an intense pulse. The spectra exhibit a periodic train of peaks 38 GHz apart. One peak is just below the limit, and with a 90 V/cm field amplitude the train ex...
September 25, 2019
We investigate two well-known approaches for extending the fewest switches surface hopping (FSSH) algorithm to periodic time-dependent couplings. The first formalism acts as if the instantaneous adiabatic electronic states were standard adiabatic states, which just happen to evolve in time. The second formalism replaces the role of the usual adiabatic states by the time-independent adiabatic Floquet states. For a set of modified Tully model problems, the Floquet FSSH (F-FSSH)...
January 22, 1998
The standard solution of the Schroedinger equation for the hydrogen atom is analyzed. Comparing with the recently established internal properties of electrons it is found, that these solutions cannot be seen as physically valid states of the electron wave. The paper therefore proposes a new model of hydrogen based on internal properties of electrons. The ground state of the hydrogen system (T=0) is an inertial aggregation within the atomic shell, the calculation yields an ato...