The time-dependent close-coupling method is applied to calculate the electron-impact ionization of a diatomic molecule with interior closed subshells. The ionization of the outer 2sσ subshell of Li2(1sσ 22pσ 22sσ 2) is carried out using a standard core orthogonalization method. At the peak of the Li2 cross section, the nonperturbative time-dependent close-coupling cross sections are found to be...

Articles you may be interested in Electric field effects in the near‐threshold photoionization spectrum of nitric oxide Shape resonance effects in the rotationally resolved photoelectron spectra of O2 The results of combined experimental and theoretical studies of the rotationally resolved photoelectron spectra of OH and OD following single-photon ionization are presented. The measured zero-kin...

The novel effects resulting from the entrainment of low mobility ions during alternating current (ac) electrospray ionization are examined through mass spectrometry and voltage/current measurements. Curious phenomena such as pH modulation at high frequencies (>150 kHz) of an applied ac electric field are revealed and explained using simple mechanistic arguments. Current measurements are utilize...

The non–resonant two–photon ionization of hydrogen–like ions is studied in second–order perturbation theory, based on Dirac’s equation. To carry out the summation over the complete Coulomb spectrum, a Green’s function approach has been applied to the computation of the ionization cross sections. Exact second–order relativistic cross sections are compared with data as obtained from a relativisti...

We report differential measurements of Ar++ ion momentum distributions from nonsequential double ionization in phase-stabilized few-cycle laser pulses. The distributions depend strongly on the carrier-envelope (CE) phase. Via control over the CE phase one is able to direct the nonsequential double-ionization dynamics. Data analysis through a classical model calculation reveals that the influenc...

coherent coupling of autoionizing states on multiphoton ionization" (1996). C. We present the experimental and theoretical investigation of the effects of the strong electromagnetic coupling of two autoionizing states (AIS's) on the photoionization properties of an atomic system. These effects are observed by probing the ladder system from the ground state of the atom through a weak two-photon ...

Recent high-resolution observations of metal absorption lines in high-redshift damped Lyα systems have shown that Al III, a tracer of moderately-ionized gas, very often has a velocity structure indistinguishable from that of low-ionization gas. Regions of ionized and neutral hydrogen in these systems are likely cospatial. The higher-ionization Si IV and C IV absorption shows a much weaker or no...

BACKGROUND Matrix effects can profoundly reduce the performance of electrospray ionization mass spectrometry. Preliminary observations indicated that the methanol used in the mobile phase could be a source of differential ionization or ion suppression. METHODS Drug stability studies, analysis of biological extracts, mixing experiments, and postcolumn infusions were used to test 9 commercial m...