Excited rare gas

De-excitation of excited rare gas atoms such as Penning ionization and related processes (see Section 3)... 

De-excitation processes of excited rare gas atoms in the lowest excited states have an important role in various phenomena in ionized gases. Recently, the importance has... 

De-excitation of Excited Rare Gas Atoms in Metastable States... 

Experimental details for the cross-section measurements were presented in the literature. Briefly, after the irradiation by electron beam pulse for a few nanoseconds, the time-dependent absorption for the atomic line transition Rg Rg -i-/zv was measured to observe the time-dependent population of the excited rare gas atoms Rg. The population of excited Rg was determined using an absorption law for the atomic lines, where the broadening of the absorption profile due to the thermal Doppler effect and due to the attractive interatomic potentials was reasonably taken into consideration. The time-dependent optical emission from energy transfer products, such as ... 

De-excitation of the excited rare gas atoms in the resonant states has been studied less extensively than that of the metastable atoms. This is due to experimental difficulties caused by the short lifetimes of the resonant atoms. There have been reported, however, several theoretical formulations [139,140] based on a long-range dipole-dipole interaction... 

As a brief conclusion of this section, the cross-section measurements for the deexcitation of excited rare gas atoms have been best performed using the pulse radiolysis method. The pulse radiolysis method has provided not only the most reliable cross sections... 

The spectrum emitted from excited rare gas atoms is rather complex studies in the visible range require a resolution of about 10 A in order to isolate a single line. Until recently small beam intensity and low detection sensitivity limited optical studies to high collision energies. 

Most studies reported below have been made with insufficient resolution in order to measure a true emission cross section. The influence of polarization of the emission on the cross section has been neglected entirely on the other hand it has been shown that the emission from collisionally excited rare gas atoms can be highly polarized.1... 

IV Deexcitation of Excited Rare Gas Atoms by Molecules Containing... 

In reactive plasmas consisting of the mixture of a rare gas with an additive host gas of polyatomic molecules, the collisional energy transfer from an excited rare gas atom to a constituent polyatomic molecule to form ions and free radicals is of great importance. 

The deexcitation cross-sections are dependent on electronic states of excited rare gas atoms and target molecules. They are compared in detail with related theoretical results to find some regularities of cross-section values in correlation with fimdamental parameters of target molecules, from which unknown cross-section values for any molecules can be estimated with enough accuracy. Availability of this estimation will be of great importance in finding new candidates of host molecules in reactive-plasma research. 

It was found, from pulse radiolysis experiments, that there were at least two temporal components to the exciplex emission, and a general mechanism for exciplex formation and decay was developed [57-67] which consists of direct reaction of electronically excited rare gas atoms with the halide source gas and ionic recombination. 

Lovelock, J.E. Measurement of low vapour concentrations by collision with excited rare gas atoms. Nature (London) 1958, 181 (4621), 1460. 

The electronically excited rare gas atom is sometimes called a super-alkali because its ionization potential is so low. There are also super-halogens and not only super-alkalis (Herschbach, 1966 Bersohn, 1976). The super-halogen has a particularly high electronic affinity NO2, with an electron affinity of about 2.4 eV, is an example so is (CN)2. Excited states of organic molecules are used as effective electron donors. Complexes of transition metals in unusually high oxidation states are keen acceptors and vice versa for complexes where the metal is nominally neutral. 

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