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Trajmar, S.

Publications and source records attributed to Trajmar, S..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Differential Cross Sections for the Electron Impact Excitation of the A(sup 3)(Sigma)(sub u)(sup +), B(sup 3)Pi(sub g), W(sup 3)(Delta)(sub u), B'(sup 3)(Sigma)(sub u)(sup -), a'(sup 1)Sigma(sub u)(sup -), a(sup 1)Pi(sub g), w(sup 1)Delta(sub u), and C(sup 3)Pi(sub u) States of N(sub 2)

Measurements of differential cross sections for the electron-impact excitation of molecular nitrogen from the ground X(sup 1)(Sigma)(sub g)(sup +)(v''=0)level to the A(sup 3)(Sigma)(sub u)(sup +)(v'), B(sup 3)Pi(sub g)(v'), W(sup 3)(Delta)(sub u)(v'),B'(sup 3)(Sigma)(sub u)(sup -)(v'), a(sup 1)(Pi)(sub g)(v'), w(sup 1)(Delta)(sub u)(v'), and C(sup 3)(Pi)(sub u)(v') levels are presented. The data are obtained at the incident energies of 10, 12.5, 15, 17.5, 20, 30, 50, and 100 eV over the angular range of 5(deg)-130(deg) in 5(deg) intervals. The individual electronic state excitation differential cross sections are obtained by unfolding electron energy-loss spectra of molecular nitrogen using available semiempirical Frank-Condon factors. The data are compared to previous measurements and to available theory. We also make several important suggestions regarding future work that, like the present, relies on the unfolding of electron energy-loss spectra for obtaining differential cross sections.

electron impact↗
NASA NTRS2000

Coherence Measurements for Excited to Excited State Transitions in Barium

Experimental studies concerning elastic and inelastic electron scattering by coherently ensembles of Ba (...6s6p (sub 1)P(sub 1)) atoms with various degrees of alignment will be described. An in-plane, linearly-polarized laser beam was utilized to prepare these target ensembles and the electron scattering signal as a function of polarization angle was measured for several laser geometries at fixed impact energies and scattering angles. From these measurements, we derived cross sections and electron-impact coherence parameters associated with the electron scattering process which is time reverse of the actual experimentally studied process. This interpretation of the experiment is based on the theory of Macek and Herte. The experimental results were also interpreted in terms of cross sections and collision parameters associated with the actual experimental processes. Results obtained so far will be presented and plans for further studies will be discussed.

Trajmar, S.↗
NASA NTRS1996

Electron Impact Excitation of C60 Adducts: Flourescence From C60OH and C60H Species

An investigation concerning possible visible and UV photon emissions by gas phase C(sub 60) ( and C(sub 70)) samples under electron impact excitation was caried out in the 180-750 nm spectral region. Radiation resembling OH (A (sup 2)pi {leads to}X (sup 2){summation}) emission bands and H Balmer series was observed. Based on our investigations, it is concluded that none of the observed emission was associated with the fullerene molecule itself but with the C(sub 60)OH and C(sub 60)H adducts (which are present in the fullerene samples). We also conclude that in these adducts, simultaneous ionization and excitation take place under electron impact and the excited ionic species (C(sub 60)+OH* and C(sub 60)+H*) decay by radiation which was observed in our experiments. These surprising results reveal an interesting new character of buckyball adducts.

gas phase emissions buckyball buckyball adducts fu↗
NASA NTRS1996

Absolute Inelastic Differential Electron Scattering Cross Sections for He, Xe, N2, and CO at Near Threshold Impact Energies for 90(deg) Scattering Angle

There is a great deal of need for accurate differential cross sections (DCSs) associated with electron impact excitation of various atomic and molecular species. These cross sections are needed for modeling of various plasma systems (ranging from lasers and material processing plasmas to planetary and astrophysical plasmas) and for guiding development of theoretical and computational schemes.

DCS beam scattering beam-beam scattering↗
NASA NTRS1996

Electron Impact Excitation of Autoionizing Levels of Kr and Xe Between the (sup 2)P(sub 3/2) and (sup 2)P(sub 1/2) Ionic Limits

We have observed electrons ejected from autoionizing levels which lie between the (sup 2)P(sub 3/2) and (sup 2)P(sub 1/2) ionic limits for Kr and Xe. Kinetic energy spectra of the ejected electrons were obtained following electron impact excitation of the target gases by using time-of-flight spectroscopy in a crossed beam experiment. Spectral features which correspond to electrons ejected from both odd and even parity autoionizing levels have been identified.

autoionizing ejected electrons↗
NASA NTRS1993

Total electron scattering and electronic state excitations cross sections for O2, CO, and CH4

Available electron collision cross section data concerning total and elastic scattering, vibrational excitation, and ionization for O2, CO, and CH4 have been critically reviewed, and a set of cross sections for modeling of planetary atmospheric behavior is recommended. Utilizing these recommended cross sections, we derived total electronic state excitation cross sections and upper limits for dissociation cross sections, which in the case of CH4 should very closely equal the actual dissociation cross section.

Kanik, I.↗
NASA NTRS1993

Electron-Impact Excitation of the B ^1SIGMA^+, C^1SIGMA^+ and E^1PI States of

Electron impact excitation of CO plays an important role in planetary atmospheres andinterstellar clouds. At the present time, serious discrepancies exist among excitation cross sectionsreported in the literature for this molecule. We measured electron impact excitation cross sections forB^1SIGMA^+right arrowX^1SIGMA^+, C^1SIGMA^+right arrowX^1SIGMA^+ and E^1PIrightarrowX^1SIGMA^+ states of CO at 100eV impact energy using electron energy-loss spectroscopy.

Kanik, I.↗
NASA NTRS1993

Total Electron Scattering and Electronic State Excitations Cross Sections for O_2, CO, and CH_4

Available electron collision cross section data concerning total and elastic scattering, vibrationalexcitation, and ionization for O_2, CO, and CH_4 have been critically reviewed, and a set of crosssections for modeling of planetary atmospheric behavior is recommended. Utilizing theserecommended cross sections, we derived total electronic state excitation cross sections and upperlimits for dissociation cross sections, which in the case of CH_4 should very closely equal the actualdissociation cross section.

Kanik, I.↗