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Three-body ionic-recombination reactions of Xe+/Br−/He leading to XeBr* excimers and their predissociation products (Xe* and Br*) have been studied by observing emission spectra in a He flowing afterglow. The branching ratios of XeBr(B):XeBr(D):Xe(6s 3P1,6p 1D2):Br(5p) in the Xe+(2P1/2)/Br−/He reaction are 0.65:0.077:0.087:0.19, while those of XeBr(B):XeBr(C):XeBr(D):Xe(6s 3P1):Br(5s) in the Xe+(2P3/2)/Br−/He reaction are 0.87:0.12:0.0040:0.0014:0.0067, respectively. The large relative formation rate of XeBr(B) in the Xe+(2P1/2)/Br−/He reaction indicated that a breakdown of the ion configuration of Xe+ occurs significantly in the Xe+(2P1/2) reaction. The XeBr(B) state is probably formed through multiple collisions with third-body He atoms, which cause a trajectory change from the entrance V[Xe+(2P1/2),Br−] potential to exit V[Xe+(2P3/2),Br−] ionic potentials via predissociation V(Xe*,Br) potentials. The large relative formation rates of XeBr(B,C) in the Xe+(2P3/2)/Br−/He reaction indicated that the ion co...

Nascent vibrational distributions of KrF(B) and XeCl(B) resulting from Kr+(2P3/2)+SF−6 and Xe+(2P3/2)+Cl−+He reactions have been determined by a spectral simulation of the bound–free B–X transition. The vibrational distribution of KrF(B) has a maximum at v’=0 and decreases exponentially with increasing v’. It is in reasonable agreement with the statistical prior distribution in which all vibrational and rotational degrees of freedom in the products are taken into consideration. It is therefore concluded that the Kr+(2P3/2)+SF−6 reaction proceeds through a long‐lived [Kr+(2P3/2)SF−6] intermediate. The vibrational distribution of XeCl(B) decreases linearly with increasing v’. It is more vibrationally excited than the prior distribution, indicating that a (Xe+Cl−He) intermediate decomposes before a complete energy randomization. The average fractions of total available energy deposited into vibrational energy of the excimer 〈fv〉 are estimated to be 5.8% for the Kr+(2P3/2)+SF−6 reaction and 16% for the Xe+(2P...

The three‐body ionic‐recombination reaction of Ar+(2P3/2)/Cl−/Ar leading to ArCl(B,C), Ar(3P2), and Cl(4s,4s’,4p,4p’,4d,5p,6s) has been studied spectroscopically in an Ar flowing afterglow. The results obtained are compared with our previous data for the Ar+(2P3/2)/Cl−/He reaction in order to examine the effects of the third‐body atom. The Ar+(2P3/2)/Cl−/Ar reaction populates lower energy states of [Ar+(2P3/2)Cl−] intermediates than the Ar+(2P3/2)/Cl−/He one, so that the branching ratio of excimer becomes large in comparison with those of predissociation channels, the lower ArCl(B) state is preferentially excited than the ArCl(C) state, the ArCl(B) state is populated in lower vibrational levels, and the electronic state distribution of Cl* shifts to lower energy. On the basis of these findings, it is concluded that the heavy Ar atom is a more efficient acceptor of the excess energy than the light He atom in the Ar+(2P3/2)/Cl−/Rg (Rg=rare gas) system.