The large polycyclic aromatic hydrocarbon molecules coronene, benzo[GHI]perylene, and anthracene have been ionized with femtosecond laser pulses at low laser intensities and the ionization process studied with velocity map imaging spectroscopy, supplemented with ion yield measurements. The electron spectra of coronene and benzo[GHI]perylene are structureless. Based on fluence and pulse duration...

Using a semiclassical rescattering model, the momentum distributions of recoil ions from laser induced single and double ionization are obtained. Not only in the case of double ionization but also in the case of single ionization, the distributions of the momentum parallel to the polarization direction of the laser field show a double-hump structure as a consequence of the rescattering. By comp...

A set of hydrodynamic equations modeling strong ionization in semiconductors is formally derived from a kinetic framework. To that purpose, a system of Boltzmann transport equations governing the distribution functions of conduction electrons and holes is considered. The charge carriers obey a degenerate gas statistics and their kinetic energy relations are arbitrary. The umklapp collisions are...

Photoelectron angular distributions (PADs) obtained from ionization of potassium atoms using moderately intense femtosecond IR fields (∼10^{12}  W cm^{-2}) of various polarization states are shown to provide a route to "complete" photoionization experiments. Ionization occurs by a net three-photon absorption process, driven via the 4s→4p resonance at the one-photon level. A theoretical treatmen...

Evolution of atomic ionization into the strong-field limit offers the opportunity to study the fundamentals of atom-laser interaction. In this study, we report on high precision measurements of the ion and electron distributions from laser-excited helium and neon atoms which reflect the changing continuum dynamics as the ionization process evolves into the pure tunneling regime. The experiments...

Inductive inference is of central importance to all scientific inquiries. Automating the process of inductive inference is the major concern of machine learning researchers. This article proposes inductive inference techniques to address three inductive problems: (1) how to automatically construct a general description, a model, or a theory to describe a sequence of observations or experimental...

Fully quantum treatment explicitly presents the high harmonic generation as a three-stage process: above threshold ionization (ATI) is followed by the continuum electron propagation in a laser field and subsequent stimulated recombination back into the initial state. The contributions of all ATI channels add up coherently. All three stages of the process are described by simple, mostly analytic...

the chemical components in the decoctions of chinese herbal medicines are not always the same as those in the crude herbs because of the insolubility or instability of some compounds. in this work, a high-performance liquid chromatography (hplc) coupled with electrospray ionization (esi) tandem mass spectrometry method was developed to explore dynamic variation patterns of aconitum alkaloids in...

The formation of the flower-inducing principle in the leaves of Xanthium pensylvanicum Wallr. has been shown by Hamner (1) to consist of at least two partial reactions: a preliminary high intensity light process, followed by a process requiring for its completion a minimum period of continuous darkness. Recently it was reported (3) that the flowering response of Xanthium may be suppressed when ...