Validity of Saha’s equation of thermal ionization for negatively charged spherical particles in complex plasmas in thermal equilibrium

2011 ◽  
Vol 18 (4) ◽  
pp. 044502 ◽  
Author(s):  
M. S. Sodha ◽  
S. K. Mishra
Keyword(s):  
Thermal Equilibrium ◽  
Thermal Ionization ◽  
Spherical Particles ◽  
Complex Plasmas

scholarly journals Механизм термической ионизации уротропина на поверхности интерметаллида NaAu-=SUB=-x-=/SUB=-

2022 ◽  
Vol 92 (3) ◽  
pp. 481
Author(s):  
М.В. Кнатько ◽  
М.Н. Лапушкин
Keyword(s):  
Excited State ◽  
Thermal Equilibrium ◽  
Degrees Of Freedom ◽  
Ion Current ◽  
Thermal Ionization ◽  
Adsorption Complex ◽  
Decomposition Reactions ◽  
Temperature Dependences ◽  
Monomolecular Decomposition ◽  
Bulk Structure

Thermal ionization of methenamine (C6H12N4) on the surface of the NaAux intermetallic compound has been studied. It has been established that the processes of decomposition, desorption and ionization of adsorbed compounds, thermally stimulated on the surface, proceed due to the accumulation of energy at the degrees of freedom of the adsorption complex, including the adsorbed compound and a solid, by the mechanism of monomolecular decomposition reactions. In this case, the decomposition of the adsorption complex is accompanied by the desorption of ions that are not in thermal equilibrium with the solid. The uniformity of the temperature dependences of the ion current and their distribution over two groups allowed us to conclude that ions are desorbed from the surface, which correspond to the decays of individual adsorbed molecules, as well as the decays of dimers formed on the surface. The decay of methenamine molecules during thermal ionization occurs in the same way as their decay in vacuum during electron ionization, which indicates the preservation of the bulk structure of methenamine molecules during adsorption and a significant lifetime of the excited state of compounds on NaAux.

STEM Study of Surface Plasmon Excitation in Small Spherical Particles

1990 ◽  
Vol 48 (2) ◽  
pp. 42-43
Author(s):  
Daniel UGARTE
Keyword(s):  
Energy Loss ◽  
Spherical Particles ◽  
Small Particles ◽  
Bulk Materials ◽  
Low Loss ◽  
Plasmon Excitation ◽  
Surface Modes ◽  
Surface Plasmon Excitation ◽  
Analytical Electron ◽  
Analytical Electron Microscope

Small particles exhibit chemical and physical behaviors substantially different from bulk materials. This is due to the fact that boundary conditions can induce specific constraints on the observed properties. As an example, energy loss experiments carried out in an analytical electron microscope, constitute a powerful technique to investigate the excitation of collective surface modes (plasmons), which are modified in a limited size medium. In this work a STEM VG HB501 has been used to study the low energy loss spectrum (1-40 eV) of silicon spherical particles [1], and the spatial localization of the different modes has been analyzed through digitally acquired energy filtered images. This material and its oxides have been extensively studied and are very well characterized, because of their applications in microelectronics. These particles are thus ideal objects to test the validity of theories developed up to now.Typical EELS spectra in the low loss region are shown in fig. 2 and energy filtered images for the main spectral features in fig. 3.

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