Ion-mobility spectrometry (IMS) in conjunction with radioactive ionization sources has been employed for field-portable applications for the past two decades. Recently, electrospray ionization (ESI) sources have been shown as a viable ionization source with IMS instruments, enabling the analysis of many nonvolatile compounds. Introduction of a liquid-sheath-flow ESI source enabled the direct an...

We present a general expression for the field ionization probability of atoms and ions under a quasistatic external electric field. While the treatments available as yet are only for the case of a single electron in the outer nl subshell, the expression obtained here is applicable to atoms and ions with any number of electrons in the outer subshell and with partially filled inner subshell~s!. W...

We have excited helium atoms from their metastable 2 3S state to Rydberg states in the range 13 < n < 50 in a two-step process via the 3 3P state using light at λ = 389 nm and 785–815 nm. Atoms in a thermal beam (100 K) cross partially overlapping laser beams of the appropriate frequencies in the counterintuitive order to exploit the high efficiency of stimulated rapid adiabatic passage. The in...

We have studied an ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at the three ambient temperatures of 77...

We have studied an ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at the three ambient temperatures of 77...

Numerous investigations have focused on DNA damage induced by ionizing radiation; however, photoionization threshold energies of nucleic acid components in aqueous solution are not known. Herein, data from gas-phase photoelectron experiments have been combined with results from self-consistent field and post-self-consistent field molecular orbital calculations and with theoretical Gibbs free en...

We have studied an ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at the three ambient temperatures of 77...

[1] This paper reports a modeling study on sprite streamer formation at subbreakdown conditions, i.e., the initiation of sprite streamers in a lightning field below the breakdown threshold field Ek. Successful formation of streamers is observed for a variety of electric fields with the lowest field of 0.3Ek when an appropriate ionization column is introduced. The simulation results also indicat...

We have studied the ionization of Rydberg–excited xenon atoms in THz-laser fields and by quantum dynamical calculations. The experimental threshold laser field strength for 10% ionization probability follows an n (ω/2π =1.04 THz) dependence (n effective principal quantum number) with additional weak resonance structures and shows that ionization does not occur by a Landau–Zener mechanism. At sc...

Singleand double-ionization processes in C6+ collisions with the He atom at an incident energy of 100 MeV/amu are studied by direct solution of the time-dependent Schrödinger equation. A time-dependent close-coupling method based on an expansion of a one-electron three-dimensional wave function in the field of He+ is used to calculate single-ionization cross sections. A time-dependent close-cou...