Angular profiles of molecular beams from effusive tube sources: I. Experiment

Rugamas, F.; Roundy, David; Mikaelian, Gary; Vitug, G.; Rudner, Mark S.; Shih, James; Smith, Daniel; Segura, Jean-Manuel; Khakoo, M. A.

doi:10.1088/0957-0233/11/12/315

Cited by 39 publications

(24 citation statements)

References 22 publications

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“…[35][36][37][38][39] That calibration requires constant Knudsen numbers for BF 3 and He to generate equal two gas densities in the collision volume, for which the head pressures behind the nozzle were about 0.5 Torr for BF 3 (4.90 Å) and 2.5 Torr for He (2.18 Å). Those were estimated based on the hard sphere model.…”

Section: Methodsmentioning

confidence: 99%

Crossed-beam experiment for the scattering of low- and intermediate-energy electrons from BF3: A comparative study with XF3 (X = C, N, and CH) molecules

Hoshino

Limão‐Vieira

Suga

et al. 2015

The Journal of Chemical Physics

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Absolute differential cross sections (DCSs) for electron interaction with BF 3 molecules have been measured in the impact energy range of 1.5-200 eV and recorded over a scattering angle range of 15 • -150 • . These angular distributions have been normalized by reference to the elastic DCSs of the He atom and integrated by employing a modified phase shift analysis procedure to generate integral cross sections (ICSs) and momentum transfer cross sections (MTCSs). The calculations of DCSs and ICSs have been carried out using an independent atom model under the screening corrected additivity rule (IAM-SCAR). The present elastic DCSs have been found to agree well with the results of IAM-SCAR calculation above 20 eV, and also with a recent Schwinger multichannel calculation below 30 eV. Furthermore, in the comparison with the XF 3 (X = B, C, N, and CH) molecules, the elastic DCSs reveal a similar angular distribution which are approximately equal in magnitude from 30 to 200 eV. This feature suggests that the elastic scattering is dominated virtually by the 3-outer fluorine atoms surrounding the XF 3 molecules. The vibrational DCSs have also been obtained in the energy range of 1.5-15 eV and vibrational analysis based on the angular correlation theory has been carried out to explain the nature of the shape resonances. Limited experiments on vibrational inelastic scattering confirmed the existence of a shape resonance with a peak at 3.8 eV, which is also observed in the vibrational ICS. Finally, the estimated elastic ICSs, MTCSs, as well as total cross sections are compared with the previous cross section data available. C 2015 AIP Publishing LLC. [http://dx

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Section: Methodsmentioning

confidence: 99%

Crossed-beam experiment for the scattering of low- and intermediate-energy electrons from BF3: A comparative study with XF3 (X = C, N, and CH) molecules

Hoshino

Limão‐Vieira

Suga

et al. 2015

The Journal of Chemical Physics

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“…It has been estimated that the localized vapor flux may be 100 times greater than that specified by the ambient pressure based on capillary flow equations. 24 Temperaturedependent measurements were carried on an Emitech K25X Peltier Cooled Stage. The stage is capable of stable operation in a temperature range of 243-348 K.…”

Section: A Experimentsmentioning

confidence: 99%

Effects of heat generation during electron-beam-induced deposition of nanostructures

Randolph

Fowlkes

Rack

2005

Journal of Applied Physics

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To elucidate the effects of beam heating in electron-beam-induced deposition (EBID), a Monte Carlo electron-solid interaction model has been employed to calculate the energy deposition profiles in bulk and nanostructured SiO2. Using these profiles, a finite element model was used to predict the nanostructure tip temperatures for standard experimental EBID conditions. Depending on the beam energy, beam current, and nanostructure geometry, the heat generated can be substantial. This heat source can subsequently limit the EBID growth by thermally reducing the mean stay time of the precursor gas. Temperature-dependent EBID growth experiments qualitatively verified the results of the electron-beam-heating model. Additionally, experimental trends for the growth rate as a function of deposition time supported the conclusion that electron-beam-induced heating can play a major role in limiting the EBID growth rate of SiO2 nanostructures.

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“…H 2 O has a permanent dipole (1.84D) that would increase its effective from that of a pure hard sphere to include soft-sphere (long range) scattering. An estimate using data from [25] of gas beam profile angular widths versus mean free paths, assuming Gaussian profile beams and that the electron beam scatters off the forward gas beam gives the result that using a lowered value in a relative flow experiment results in DCSs that are lower by the ratios of , i.e., 1:75. Figure 2 shows our electron-H 2 O ICSs, which are compared to both total cross sections (TCS) and other ICS values.…”

mentioning

confidence: 99%

Low Energy Elastic Differential Electron Scattering fromH2O

et al. 2008

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Normalized differential cross sections for elastic (rotationally averaged) electron scattering from gaseous water (H2O) are obtained using the relative flow method against helium with a thin aperture collimating source of gas instead of a tube. This method obviates the use of gas kinetic molecular diameters for helium or water. Our measurements are found to be largely in quantitative disagreement with past differential elastic electron scattering measurements and suggest that present recommended electron scattering total cross sections for water be revised.

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Angular profiles of molecular beams from effusive tube sources: I. Experiment

Cited by 39 publications

References 22 publications

Crossed-beam experiment for the scattering of low- and intermediate-energy electrons from BF3: A comparative study with XF3 (X = C, N, and CH) molecules

Crossed-beam experiment for the scattering of low- and intermediate-energy electrons from BF3: A comparative study with XF3 (X = C, N, and CH) molecules

Effects of heat generation during electron-beam-induced deposition of nanostructures

Low Energy Elastic Differential Electron Scattering fromH2O

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