Structural Isomers and Excited States of HN3

Multiconfigurational wavefunctions were adopted to study structural isomers, their isomerization reactions and excited states of $HN_3$. In addition to the known linear isomer, two new structural isomers were found. The three isomers can be classified as sp, $sp^2$ and $sp^3$ hybridized species, respectively. The sp3 hybridized species turned out to be the second most stable. Large reaction barriers among these species prevent thermal isomerizations. A low-lying $^3A exists with a relative energy of 13.5 kcal/mol. Dramatic re-hybridization and bond elongation was found in the first excited $^1A"$.