REACTIONS OF PULSED-LASER ABLATED AL ATOMS WITH H-2 - INFRARED-SPECTRA OF ALH, ALH2, ALH3, AND AL2H2 SPECIES

Pulsed laser evaporated Al atoms were reacted with H-2 in excess argon during condensation at 10 K. Matrix infrared spectra, deuterium substitution, and ab initio calculations identified AlH, AlH2, AlH3, and several Al2H2 species. The spectra are complicated by H-2 complexes with the major products. Activation energy for these reactions was provided by hyperthermal aluminum atoms from the laser ablation process. Absorptions for AlH3 increased markedly on photolysis, which facilitated their identification.