Structural isomers and excited states of HN₃

Multiconfigurational wavefunctions were adopted to study structural isomers, their isomerization reactions and excited states of HN₃. In addition to the known linear isomer, two new structural isomers were found. The three isomers can be classified as sp, sp² and sp³ 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''.