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Rhodes Ch. (ed.) Eximer lasers (Springer, 1984)(KA)(600dpi)(T)(276s)_EO_.djvu |
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Size 2.6Mb Date Oct 20, 2002 |
and VIII atoms will be included in the class of "B" atoms and we have divided
the discussions of specific systems into the six cases of Group I, II, or III atoms
paired with Group II or VIII atoms...
A major fraction of the deposited energy is presumed to
go into electronic excitation, ionization, and gas heating...
This applies to the
strongly bound as well as the weakly bound excimers as long as they do not
involve light atoms such as H or He and the buffer gas densities are in the
typical 1020 cm range...
In addition they are applicable from the
wings of atomic lines on through the associated molecular bands...
Since the CFCP is a classical principle, it is also appropriate to use a
classical canonical phase-space distribution to describe the equilibrium distri-
distribution of states of nuclear motion [5.6]...
If each line is collisionally broadened by the buffer gas to a few
cm, then each excited state typically radiates into a few percent of the band...
The absorption coefficients, and effectively the emission
coefficients using relations in Sect...
This condition
is most easily satisfied at the longest wavelength region of the A-X bands,
recalling, of course, that the gain drops rapidly in this region...
Since the Li-He
system has very slight or no ^4-state attraction, the molecular state populations
will be in equilibrium with the gas temperature under all feasible conditions...
However, only in the past two years was
it discovered that the strong excimer bands occur very far from the forbidden
atomic lines...
Visible and uv excimer bands associated with the n3P and nlP-^nlS
(ground state) transition may be viable excimer laser candidates, and even the
near infrared n3P^(n-lKD and nlP-^{n-\)lD transitions might be of
interest for Ca, Sr, and Ba...
As in the Hg2 case which follows, this may
be an effective radiative rate due to an excited population distributed thermally
between the 31 and 3O~ states, with the latter metastable...
Absorption (Kv) and stimulated
emission (Gv) coefficients for Hg vapor at
T=1300K, [Hg] = 1019cm~3, [Hg*] = 1017
cm, where Hgf refers to the 35^.0eV
excimer states in Fig...
The lower gain-coefficient Tl Xe system
is much more difficult to achieve laser action in, although it could attain higher
power and energy densities without superfluorescence losses if successful...
Separate calculations of the
electronic structures of HgCl2, HgBr2 [5.68], Hg2F2, and Hg2Cl2 [5.69] have
been made...
Ion-
pair energies are typically ~ 1.7 times ionization energies, and generally only
one excimer is formed per ion pair...
Therefore, the dis-
discussions following will concentrate on the pure Hg and alkali-noble gas cases...
Another potential major problem is cavity quality deterioration due to
index of refraction variations, i.e., loss of medium homogeneity...
These excimers exhibit radiative
transitions in the wavelength region from 230 nm (Ar2Cl) to 670 nm (Xe2F)...
Their identification was made through the observation that these
emissions become dominant at high rare-gas densities, under which conditions
clustering reactions might be expected to be important...
The magnitude of this shift and the broadband nature of the
Triatomic Rare-Gas-Halide Excimers
185
Table 6.1...
Figure 6.5 shows the binding of Xe2Cl* relative to XeCl* + Xe and the very
repulsive nature of the covalent states at the equilibrium geometry of the lowest
ionic state (R~5.5a0)...
The primary steps in a basic kinetic model for trimer formation in argon-
buffered rare-gas-halide mixtures under intense e-beam excitation is shown in
Fig...
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