Observations show significant Hα-emissions in the Galactic halo near the edges of cold gas clouds of the Magellanic Stream. The source for the ionization of the cold gas is still a widely open question. In our paper we discuss the critical velocity effect as a possible explanation for the observed Hα-emission. The critical velocity effect can yield a fast ionization of cold gas if this neutral ...

We have theoretically studied the effect of dissociative autoionization on the photoelectron energy spectrum in (1+2)-photon above threshold ionization (ATI) of H2 molecules. We have considered excitation from the ground XΣg (v = 0, j) state to the doubly excited autoionizing states of Σu and Πu symmetry, via the intermediate resonantBΣu (v = 5, j) states. We have shown that the photoelectron e...

Ionization suppression can be defined as the decrease of photoinduced atomic ionization rates with an increased applied field intensity. The temporal and spatial intensity distribution of a focused laser pulse introduces difficulty in observing ionization suppression. An analysis of the effect of a temporally Gaussian laser pulse on ionization suppression from Rydberg levels is given. It is fou...

The effect of an exocyclic substituent on the ionization potential of primaquine, an important antimalarial drug, was investigated using density functional theory methods. It was found that an electron-donating group (EDG) makes the ionization potential decrease. In contrast, an electron-withdrawing group (EWG) makes the ionization potential increase. Among all the exocyclic positions, a substi...

The purpose of the present work was to evaluate the synergistic effect of ionization type, sample preparation technique, and bio-fluid on the presence of matrix effect in quantitative liquid chromatography (LC)-MS/MS analysis of illicit drugs by post-column infusion experiments with morphine (10-microg/mL solution). Three bio-fluids (urine, oral fluid, and plasma) were pretreated with four samp...

The most widely used ionization techniques in liquid chromatography-mass spectrometry (LC-MS) are electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). All three provide user friendly coupling of LC to MS. Achieving optimal LC-MS conditions is not always easy, however, owing to the complexity of ionization processes and t...

Strong-field ionization of atoms by circularly polarized femtosecond laser pulses produces a donut-shaped electron momentum distribution. Within the dipole approximation this distribution is symmetric with respect to polarization plane. The magnetic component light field known shift forward. Here, we show that non-dipole effect not only in strong-field ionization. We find an electric arises due...