Multiple ionization of mercury by successive electron impacts

1968 ◽  
Vol 46 (17) ◽  
pp. 1905-1913 ◽  
Author(s):  
P. A. Redhead ◽  
S. Feser
Keyword(s):  
High Current Density ◽  
Ionization Probability ◽  
Ion Current ◽  
High Current ◽  
Mercury Ions ◽  
Multiply Charged ◽  
Multiple Ionization ◽  
Charge Multiplicity ◽  
Slow Electrons ◽  
Charged Ions

Mercury ions of charge multiplicity up to n = 9 have been formed by repeated collisions of slow electrons (less than 150 eV) with ions trapped in an electron beam of high current density (~5 × 10−2 A cm−2). Ion current is observed at electron energies below the ionization potential for all multiply charged ions up to n = 8 and is ascribed to collision sequences involving metastable states of the ions (eN/eNm/ee(N + 1), where N represents an ion of charge multiplicity n). All the breaks observed in the ionization probability curves for [Formula: see text] can be explained in terms of collision sequences involving spectroscopically known metastable levels as limiting steps. Measured ionization potentials of the highly ionized species up to n = 9 are in reasonable agreement with extrapolation of spectroscopic values.

scholarly journals Вероятность ионизации атомов, распыленных при бомбардировке поверхности металлов одно- и многозарядными ионами

2022 ◽  
Vol 92 (2) ◽  
pp. 315
Author(s):  
С.Ф. Белых ◽  
А.Д. Беккерман
Keyword(s):  
Electron Excitation ◽  
Ionization Probability ◽  
Multiply Charged Ions ◽  
Local Electron ◽  
Multiply Charged ◽  
Clean Metal Surface ◽  
Singly Charged ◽  
Charged Ions ◽  
Analytical Expressions ◽  
Clean Metal

The processes of ionization of atoms sputtered under bombardment of clean metal surface by singly and multiply charged ions with kinetic energy of several keV were studied. Within the framework of simple phenomenological model of ion formation, the relaxation of local electron excitation in metal was taking into account. Analytical expressions for estimation of ionization probability of sputtered atoms was obtain. It was shown, that in comparison with singly charged ions, bombardment of metals with multiply charged ions results to significant increase of ionization probability of sputtered atoms due to more efficient excitation of electrons and increase of relaxation time of this excitation.

scholarly journals Thermodynamic properties of nonideal plasmas with multiple ionization and Coulomb and hard-core interactions

1990 ◽  
Vol 8 (4) ◽  
pp. 753-762 ◽  
Author(s):  
Torsten Kahlbaum ◽  
Andreas Förster
Keyword(s):  
Thermodynamic Properties ◽  
Hard Core ◽  
Mass Action ◽  
Free Electrons ◽  
Heavy Particles ◽  
Multiply Charged ◽  
Multiple Ionization ◽  
Nonideal Plasmas ◽  
Charged Ions ◽  
Mean Charge

We present a theoretical approach to the thermodynamic properties of nonideal plasmas consisting of neutral atoms, multiply charged ions, and free electrons. Starting with the free energy, we describe the ionization equilibrium of this system by a coupled set of mass action laws (Saha equations). Our model of interaction takes into account Coulomb forces between all charged particles and hard-core forces between all heavy particles and the electrons. The influence of multiple ionization and different interaction parts on plasma composition, mean charge, and equation of state is discussed for xenon. Finally, we show the potential occurrence of the plasma phase transition.

Multiple ionization in carbon monoxide by successive electron impacts

1969 ◽  
Vol 47 (22) ◽  
pp. 2449-2457 ◽  
Author(s):  
P. A. Redhead
Keyword(s):  
Reasonable Agreement ◽  
Energy Levels ◽  
Ion Sources ◽  
Mass Spectrometers ◽  
Trapped Ion ◽  
Appearance Potential ◽  
Multiply Charged ◽  
Multiple Ionization ◽  
Charged Ions ◽  
Potential Curves

Appearance potential curves for the multiply-charged ions of carbon and oxygen (up to C4+ and O6+ for electron energies less than 200 eV) have been measured in two mass spectrometers fitted with trapped-ion sources. Trapping of the C+ and O+ ions is not as efficient as for ions produced without dissociation because of the initial kinetic energies of the dissociatively produced ions. The predominant collision sequences involve the formation of CO+ as the first step rather than the dissociative ionization of CO. Ionization potentials estimated from measured appearance potential curves are in agreement with spectroscopically determined values. Most of the other breaks that were repeatedly observed in the appearance potential curves are in reasonable agreement with energy-limiting steps in the collision sequences corresponding to transitions between spectroscopically known energy levels of the ions. Two observed transitions (in O4+ and O5+ appearance potential curves) cannot be explained in terms of spectroscopically known energy levels and may result from highly-excited, long-lived states of O2+ and O4+, respectively. The threshold of the C4+ appearance potential curve indicates the existence of a metastable state of C3+ not previously observed.

MULTIPLE IONIZATION OF THE RARE GASES BY SUCCESSIVE ELECTRON IMPACTS (0–250 eV): I. APPEARANCE POTENTIALS AND METASTABLE ION FORMATION

1967 ◽  
Vol 45 (5) ◽  
pp. 1791-1812 ◽  
Author(s):  
P. A. Redhead
Keyword(s):  
Electron Emission ◽  
Ion Source ◽  
Metastable States ◽  
Rare Gases ◽  
Trapped Ion ◽  
Sharp Maximum ◽  
Multiple Ionization ◽  
Metastable Ions ◽  
Charge Multiplicity ◽  
Charged Ions

Multiple ionization of the rare gases has been examined in a mass spectrometer with a trapped-ion source. Ions with charge multiplicity up to n = 2 (He), n = 5 (Ne), n = 6 (Ar), n = 7 (Kr), and n = 10 (Xe) were observed with electron energies less than 250 eV. For He and Ne the thresholds agree with spectroscopic values of the ionization potentials, indicating a process of the form eN/ee(N + 1), where N represents an ion of charge multiplicity n. For Ar, Kr, and Xe, processes involving metastable states of the ion are also observed, eN/eNm; eNm/ee(N + 1). The estimated energies of the metastable levels of Ar+, Kr+, Xe+, Ar2+, and Xe2+ are in agreement with spectroscopic values. The energies of the metastable states of Ar+, Kr+, and Xe+ are in agreement with measurements of Auger electron emission from metals by metastable ions. The metastable levels estimated for the more highly charged ions (up to n = 5 for Ar, n = 6 for Kr, and n = 8 for Xe) have not been observed previously. The excitation functions of the metastable levels of Ar+, Kr+, and Xe+ are very similar and show a very sharp maximum near threshold.

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