Reactions of metastable inert gas atoms

Energy disposal in the reactions of electronically excited inert gas atoms with halogen-containing molecules has been studied by observing the ultraviolet or visible emission spectra of the inert gas halide exciplex products under flow or molecular beam conditions. The experimental information consists of branching ratios for the formation of different electronic states of the inert gas halide, vibrational population distributions (obtained by computer simulation of the bound-free spectrum) and the degree of polarisation of the chemiluminescence emission. The metastable inert gases have ionisation potentials that are very similar 

There is little, if any, difference in the reactions of the different spin-orbit states for Xe (3P2il) and Kr (3P21) [603], but differences are noted for the reactions of Ar (3P2il 0) [603, 606]. The reactions Xe + BrCN, ICN [603, 609] do not give rise to emission from any xenon halide product, but do show emission from CN (B2D+ and A2II), which results from the initially formed inert gas cyanide (Rg+CN-) rapidly predissociating to give Rg + CN.  

Reactions of electronically excited inert gas atoms (see Appendix 1) 

8) [603, 607] and is similar in both the B and C electronic states of RgX. (These states are very close in energy.) For the reactions of Xe with X2 eind XY, the vibrational energy distribution is composed of two components [603], a portion described by a linear surprisal and a flat part. A consequence of this is that Fv f, v ci,  

Reaction Reagent preparation System Product detection Information (Fg) N-e Ref. 

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Another type of reaction that may be used to create reactants is the collisional dissociation of a molecule by some electronically excited species, usually an inert gas atom [28]. Uranium atoms have been generated [29] by the collisional dissociation of uranocene by metastable argon atoms. This is an attractive alternative to the problems associated with the vaporisation of uranium. 

Moore et al. (2004) reported on the use of metastable atom bombardment (MAB) ionization and HRMS in the positive ion mode for the detection of CPs [34]. Using an inert gas like argon, MAB ionization generates ions via an electrophilic reaction of a metastable atom with the analyte of interest. Figure 10 shows a comparison of ECNI and positive ion MAB mass spectra. 

The diazo reactions in this chapter are characterized by processes run either in the gas phase, in relatively inert matrices, or in — typically, but not exclusively — aprotic and comparatively apolar solvents, either thermally or photolytically or with transition metal catalysis of various types. The metastable intermediates are carbenes (RR C ), i. e., neutral, apparently divalent, carbon compounds, or their transition metal complexes (coined carbenoids, see later in this section). It is interesting to recall that the synthesis of a compound that we now call a carbene, namely methylene (H2C ), was already attempted in the early 19th century, i.e., before the tetravalency of carbon was established. Dumas (1835) and Regnault (1839) thought then that it should be possible to obtain a compound consisting of one carbon and two hydrogen atoms by dehydration of methanol (a compound of which only the atomic ratio 1C 4H lO was then known). ... 

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