Recent experiments on multiphoton ionization in intense laser fields have revealed that the photoelectron spectrum consists of a large number of peaks. Under certain pulse duration and laser intensity conditions, the spectrum appears shifted towards lower energies and the interval between two consecutive peaks is not equal to the photon energy. The theoretical explanation based on a classical d...

We present a numerical method for investigating the non-perturbative quantum mechanical interaction of light with atoms in two dimensions, without a basis expansion. This enables us to investigate intense laser-atom interactions with light of arbitrary polarization without approximation. Results are presented for the dependence of ionization and high harmonic generation on ellipticity seen in r...

From the pulse length dependence of the absorption of intense ultrashort laser pulses focused inside fused silica, we reveal the role field-assisted collisional ionization plays in the multiphoton ionization process. This constitutes a cold avalanche ionization mechanism that persists at pulse lengths considered too short for a traditional avalanche.

We have obtained rotationally resolved pulsed field ionization-photoelectron ~PFI-PE! spectra of O2 in the energy range of 16.0–18.0 eV, covering ionization transitions O2 (a Pu , v 50 – 18,J) ←O2(X Sg , v950,N9). Although these vibrational PFI-PE bands for O21(a Pu , v) have significant overlaps with those for O2 (X Pg) and O2 (A Pu), we have identified all O2 (a Pu , v 50 – 18) bands by simul...

Fully quantum and classical trajectory Monte Carlo calculations are performed for a Rydberg alkali atom that is kicked by a pulsed electric field. The two calculations are compared to recent experimental results through the ionization probability versus peak field strength. The energy distribution of the final electrons are compared between the two calculations. There is a qualitative differenc...

It is demonstrated that field ionization mass spectrometry has a potential application for the detection of neutral species involved in organic plasmas. In FI mass spectra of r.f. glow discharge plasmas of aromatic compounds, reaction products were detected mainly at higher mass regions, reflecting that polymerization reactions were leading processes in these plasmas. For olefine compounds, on ...

Internal orbits of experimentally analyzed antihydrogen (H) atoms depend as much on an external magnetic field as on the Coulomb force. A circular "guiding center atom" model is used to understand their field ionization. This useful model, assumed in the theory of three-body H recombination so far, ignores the important coupling between internal and center-of-mass motion. A conserved pseudomome...

We present a direct comparison between calculated and measured ionization in Li and Rb when an initially bound Rydberg electron is stripped from the atom by ramping an electric field @0.415 V/~cm ns!#. We describe the method used to calculate the field dependence of the ionization; the method can be used to evolve the population from field strengths where three or more n manifolds cross to the ...

Quantum calculations of a (1+1)-dimensional model for double ionization in strong laser fields are used to trace the time evolution from the ground state through ionization and rescattering to the two-electron escape. The subspace of symmetric escape, a prime characteristic of nonsequential double ionization, remains accessible by a judicious choice of 1D coordinates for the electrons. The time...