Gas or gaseous mixtures that may lead to the formation of these molecules is a quasi-ideal laser medium since the population inversion[citation needed] is directly obtained when the excimer is formed.

The other consequence of the unstable ground state is that the excimer or exciplex species must be generated by an external excitation (either through a discharge, an electron beam, microwave, or radiation).

Although discharge lamps based on low-pressure mixtures of xenon and a chlorine donor emit incoherent light, they are reliable and easy to operate.

In 1991, Prosperio et al.[24] demonstrated the existence of XeCl2 in the gaseous state, which is important for lasing kinetics, although it emits an uninteresting infrared light.

The reasons given are: Three years later Lorentz et al.[33] performed experiments at high pressures (a few atmospheres) in a mixture containing (Ar/XeCl2) and found an emission centered at 450 nm which was attributed to XeCl2.

This is true even if the absorption phenomena occur on the side of shorter wavelengths and therefore limits the laser action at the red region of the electromagnetic spectrum from light emission.

For the minimum potential curves corresponding to almost the same value of the internuclear distance (re#0.3 nm), the energy difference measured experimentally is about 9940 cm−1.

[53][55] The Van der Waals force between atoms[78] is not strong enough in state X to explain the presence of a potential well that when low (the depth is in the order of kilotorr)[clarification needed] can contain between 12 and 20 vibrational levels (see Table 3).

Besides the previously mentioned study by Ewing and Brau,[56] the old theoretical work of Hay and Dunning are among the doubtful determinations[49] which will be broached soon.

In contrast, no conclusion can be drawn statistically given the small number of measurements of state C. However, further analysis will illuminate despite the non-matching character values in Table 6.

Hay and Dunning[49] give correct forecasts, as does the vibrational structure study by Tellinghuisen et al..[55] The following expression denotes rotational energy: Erot(M) = B’.K’ef – D’.

When they are in a configuration belonging to metastable states np5(n+1)s1, (n = 5 for xenon), rare gases possess properties of polarizability and elastic scattering similar to those of alkali metals.

[95] The valence electron, s, of the excited rare gas has a bond energy close to that of the alkali metal that follows it in the periodic table.

[96][97][98] Thus, an excited xenon has an electronic structure close to that of caesium, so that it can react with a chlorine donor in order to form XeCl*.

[50] The atom Rg and the molecule RX follow when they approach the lowest adiabatic potential and the reaction proceeds by the orbital mechanism controlled at the crossover of the ionic-covalent.

Critical factors regulating the branching ratios are the potential energies interrelated with the molecular ion (VI), the Rydberg group close to the ionization (VII) or an initial excited atom (VIII).

This decision is justified by the fact that for Xe* + Cl2 we have VII > VI > VIII, which according to Simons[107] fixes an unlikely channel for the excitation transfer.

This shows the need for new measures to confirm the available experimental results and estimate the role of other states that do not fail to form if one makes use of, as for the lasers, non-selective modes of excitation.

Some authors argue for rate constants neighboring state v=0 if HCl is vibrationally excited, but this results are based on analogies.

The 6s states do not come into play in the production of XeCl* to the extent that they give rise to collisions with molecules of vibrationally excited HCl.

In ternary mixtures, RgCl exciplexes could be synthesized, possibly leading to the formation of XeCl* through so-called displacement reactions.

The corresponding spectra demonstrated in Figure 11 was observed by virtually all authors who studied mixtures that were based on xenon and a chlorine donor.

[81] The width and oscillatory nature of these lines are bound to the existence of transitions arising from high vibrational levels of excited radiative states.

Taking reaction (9) into account, the set of values of kH must be revised downward except for Rives et al..[16] A confidence interval is difficult to obtain in these conditions.

Rives et al.[16] results leave open to question whether this process is computable, considering its weak rate constant.

This shows that the rate constants increase regularly when the vibrational level, v, of XeCl* is higher and the rare gas, Rg, is heavier.

This process induces the highest destruction, indicating that XeCl(B) synthesized with high vibrational excitation is quickly relaxed by binary collision with neon and (probably) also by xenon.

Initially, the potential curves of the different states were plotted by maintaining a constant and equal Xe-Xe distance at 3.25 Å (figure 16).

[101] According to Last and George,[43] the Xe–Cl–Xe linear molecule ought to have produced an emission approaching the ground state at 321 nm and the transition moment should be elevated to 3.9 D. As of 2014, however, no experiment confirms this prediction.

[citation needed] A theoretical study[195] attributes this to the polarization of the xenon matrix by Xe2+Cl− and by Van der Waals forces.