“…A number of groups have used hydrogen halides as precursors in the investigations of the properties and reactions of these atoms. [1][2][3][4][5][6][7][8][9][10][11] One of the most important facts has been the mobilization and subsequent disappearance of hydrogen atoms at 30-40 K. 2,3,6,7,9,10 UV excitation of rare-gas matrices doped with halogen atoms leads to charge-separation and permanent trapping of positive and negative charges as shown by Fajardo and Apkarian. [12][13][14] As a consequence of charge separation and trapping, several molecular ions such as (Xe 2 H) ϩ , (Kr 2 H) ϩ , (Ar 2 H) ϩ , (I 2 H) Ϫ , (Br 2 H) Ϫ , and (Cl 2 H) Ϫ , have been observed.…”