Concentration dependence of effective ionization potential in Penning mixtures

1986 ◽  
Vol 249 (2-3) ◽  
pp. 426-428 ◽  
Author(s):  
Tadeusz Z. Kowalski ◽  
Juliusz Zając
Keyword(s):  
Ionization Potential ◽  
Concentration Dependence ◽  
Effective Ionization

scholarly journals Recent studies of the spectrum of V1016 Cygni

1982 ◽  
Vol 70 ◽  
pp. 161-164
Author(s):  
G. Muratorio ◽  
M. Friedjung
Keyword(s):  
Radial Velocity ◽  
Ionization Potential ◽  
Radial Velocities ◽  
Emission Lines ◽  
Computer Programme ◽  
Half Maximum ◽  
The Mean ◽  
Effective Ionization

Two coudé spectra of V1016 Cyg taken on June 24 and 27, 1979 were reduced, using a computer programme developed in Marseille. Radial velocities and full widths at half maximum were measured for the emission lines, and are summarized in the following table were VR is the mean radial velocity in km s-1, DV the velocity corresponding to the mean FWHM and Xi the effective ionization potential for the ion.

Teoretical Tools for Practical ALCHEMI

2001 ◽  
Vol 7 (S2) ◽  
pp. 348-349
Author(s):  
L. J. Allen ◽  
M. P. Oxley
Keyword(s):  
Ionization Potential ◽  
Cross Sections ◽  
First Principles Calculations ◽  
Ionization Cross ◽  
Precise Shape ◽  
Atomic Scattering ◽  
Computationally Intensive ◽  
Ionization Cross Sections ◽  
Shell Ionization ◽  
Effective Ionization

Precisely known atomic scattering factors are essential for accurate atom location by channelling enhanced microanalysis (ALCHEMI) based on inner-shell ionization.1 For ALCHEMI using energy dispersive x-ray analysis (EDX), first principles calculations of ionization cross sections, realistically modeling the “delocalization” of the ionization interaction, give excellent agreement with experiment.2 Such calculations are complex and computationally intensive. Hence, simple analytic forms are often assumed to describe the ionization potential. However such analytic forms require prior knowledge of the “delocalization” of the effective ionization interaction. Such an approach assumes that the precise shape of the ionization potential is not important but that at least the half width at half maximum (HWHM) should be accurately estimated, for example using estimates of the HWHM from root-mean-square impact parameters for ionization. However this is generally not a good approximation3 and we have provided more realistic estimates (Fig. 1).

An Attack on the Contamination Problem in the Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 368-368
Author(s):  
J. J. Kelsch ◽  
A. Holtz
Keyword(s):  
Electron Microscope ◽  
Pressure Gradient ◽  
Ionization Potential ◽  
Simple Solution ◽  
Specimen Surface ◽  
Contamination Rate ◽  
Local Pressure ◽  
High Ionization ◽  
Hydrocarbon Molecules ◽  
Contamination Problem

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.

Concentration dependence of the properties of gelatin and iota-carrageenan systems at the gel point

1996 ◽  
Vol 93 ◽  
pp. 819-827 ◽  
Author(s):  
C Michon ◽  
G Cuvelier ◽  
B Launay ◽  
A Parker
Keyword(s):  
Concentration Dependence ◽  
Gel Point
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