MATRIX INFRARED SPECTROSCOPIC AND AB-INITIO STUDIES OF ZNH2, CDH2, AND RELATED METAL HYDRIDE SPECIES

A heated microwave discharge source of zinc and cadmium atoms and of their resonance radiation was used to form ZnH2 and CdH2 for infrared spectroscopic study of the matrix-isolated molecules. The reactive resonance lamp source also gives ZnH, CdH, and other related hydride species. The same hydrides have been prepared using pulsed-laser ablation of zinc and cadmium targets as the metal atom source. The ZnH2 spectrum observed here is in agreement with that reported in earlier thermal/photolysis experiments; CdH2 has an analogous spectrum. Coupled cluster calculations using 20-valence electron pseudopotentials give nu(2) and nu(3) values only 1-2% too high for ZnH2, though agreement is not as good for CdH2, with nu(2) computed 2-4% lower and nu(3) computed 2-4% higher than observed. The photosensitive dizinc species Zn2H and Zn2H2 have been identified with the help of MP2 calculations and deuterium substitution.