Ionization of NF3 by electron impact

The ionization and dissociative ionization of NF₃ by electron impact has been measured by Fourier transform mass spectrometry (FTMS). The total ionization cross-section rises to a maximum value of 2.4±0.4×10⁻¹⁶ cm² at 140 eV. Estimates of the total single ionization cross-section using ab initio energies with the binary encounter Bethe (BEB) [Y.K. Kim, M.E. Rudd, Phys. Rev. A 50 (1994) 3594] or Deutsch–Märk [Int. J. Mass Spec. 197 (2000) 37] models are roughly twice the measured values. The partial cross-sections creating NF_x⁺ (x=0, 1, 2, 3), F⁺, and NF_x²⁺ (x=1, 2, 3) are reported. Differences between the FTMS results and quadrupole data and fast atom beam results of Tarnovsky et al. [Int. J. Mass Spectrom. Ion Processes 133 (1994) 175] are discussed.     

Plasma physics issues in gas discharge laser development

An account is given of the interplay between partially ionized plasma physics and the development of gas discharge lasers. Gas discharge excitation has provided a wide array of laser devices extending from the soft X-ray region to the far infrared. The scaling of gas discharge lasers in power and energy also covers many orders of magnitude. The particular features of three regimes are discussed: short wavelength lasers (deep UV to soft X-ray), visible and near UV lasers, and infrared molecule gas lasers. The current status (fall, 1990) of these areas is reviewed and an assessment is made of future research topics that are perceived to be important     

Condensation reaction of C4H4 with pyridine

C₄H₄⁺ reacts with pyridine (C₅H₅N) via the channels of proton transfer, charge transfer and condensation with H-elimination. The condensation reaction is of general interest in terms of basic chemistry and is the focus of the present study. By means of theoretical calculations and Fourier transform mass spectrometer experiments using deuterated pyridine and substituted pyridines, the structure of the product ion and the reaction pathways are investigated. From the experimental results we find that the H atom that is eliminated can originate from either pyridine or C₄H₄⁺. The experiments show that elimination of an H atom from C₄H₄⁺ is preferred and that there is an observable kinetic isotope effect. By replacing H atoms with methyl groups in ortho positions of pyridine, the experimental results also suggest possible steric blocking to the condensation. Based on the experimental observations and results of theoretical calculations of several possible structures of intermediates, transition states, and final product ions, a possible reaction scheme for the condensation-H-elimination is discussed.