The paper considers the possibility of using a low-pressure dielectric barrier discharge (DBD) as a plasma source for the active medium of a He–Ne-laser. The results of a spectroscopic study of the ...decay stage of a DBD plasma of a cylindrical configuration with a pronounced inverse population of the upper level of the 2
p
5
5
s
configuration, which makes the line of 632.8 nm one of the brightest in the visible region of the spectrum, are presented. Based on the analysis of data on the populations of the excited levels of the neon atom and the metastable levels of helium 2
1
S
0
and 2
3
S
1
, it is shown that in the early stage of the DBD afterglow at helium pressures of a fraction of a Torr, the distribution of populations over the 2
p
5
5
s
and 2
p
5
4
d
levels of the neon atom, which is characteristic of the excitation transfer mechanism, is realized. In the late afterglow with the departure of helium atoms He2
1
S
0
, emission in the visible region of the spectrum is formed mainly by transitions from levels of the 2
p
5
3
p
, configuration, the population of which is associated with He(2
3
S
1
) atoms. At this stage, the population of the 2
p
5
5
s
and 2
p
5
4
d
states by electron–ion recombination processes is ineffective and does not lead to the formation of population inversion. As an optimal solution in terms of the 632.8 nm line brightness in the afterglow, it is proposed to use a discharge with electrodes along the outer surface of a cylindrical discharge tube, initiated at frequencies that exclude the recombination stage of the afterglow.
The possibility of obtaining the inverse population of the excited states of hydroxyl molecules generated in low-pressure discharge plasma in an Ar–H
2
O mixture was studied. The possibility of ...inversion of both the
A
2
Σ
+
state relative to the
X
2
Π ground state and inside the vibrational-rotational structure of the levels of the
A
2
Σ
+
excited state of the OH molecule was analyzed.
The population of transition states of friction-induced chemical processes and similar thermo-induced reactions is analyzed. Friction is shown to be a unique natural phenomenon that involves the ...occurrence of highly inverse transition states of chemical interaction between contact material particles, as opposed to thermally populated transition states analogous in terms of the energy level of the reactions. It is found that in evaluating the population of transition states of mechano- and thermoactivated reactions, the specific chemical interactions do not matter and only the energies of the transition states of the thermo- and mechanoactivated processes are of importance.
PDF
