Alkaline earth atoms distribution

The reactions of alkaline earth atoms with alkali halide molecules are especially noteworthy because laser-induced fluorescence has been employed in these crossed-molecular beam experiments to measure the product internal state distributions as a function of scattering angle. For Ba + KC1 and Ca + NaCl, both the atomic and diatomic products were detected. 

Figure 3. Conditional probability distributions for the valence electrons of the alkaline earth atoms in their ground states, for various values of the distance between the nucleus and one valence electron. The results are taken from calculations of Ref. 27.

Angular distribution measurements of reactive scattering of alkaline earth atoms A by halogen molecules X2 have been reported80 for Ba + Cl2 and more extensively81-82 for Ba, Sr, Ca, Mg with Cl2, Br2, IC1, BrCN. The reactions form monohalide products AX, thus following primarily the reaction path... 

The second electron jump occurs with very high probability in the reactions of alkali dimers with polyhalide molecules (see Section II.B), resulting in the capture of both alkali atoms as bound alkali halides MX. Thus, it would be very interesting to see whether the dihalides AX2 become prominent reaction products in the alkaline earth atom reactions with polyhalide molecules. Unfortunately, angular distribution measurements are presently equivocal on this point (see Section III.A). 

Sr -t-HCl, extremely narrow vibrational distribution. It appears that a much higher fraction of the reaction energy appears as product vibration than is the case for the reactions of ground state alkaline earth atoms with HX. In the case of the excited atom, reaction takes place on the triplet rather than the singlet surface correlating with ground state products. The transition from covalent reagents... 

There is now extensive evidence that all closed shell molecules, including those to be discussed here, reside in the droplet s interior and hence are classified as heliophilic. Only alkali and alkaline earth atoms and their small clusters appear to be heliophobic and remain attached at the surface of the droplets. Thus, as additional heliophilic molecules are added they will encounter and recombine with those already present in the droplet interior. This was first observed spectroscopically for SFs inside droplets consisting of 4 10 He atoms. Fig. 7.4 shows the depletion signal measured with the laser tuned to the different infra-red bands of each of the small oligomers.The resulting distribution can be invariably fitted by a Poisson distribution... 

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