AB-INITIO STUDY OF PERNITRIC ACID - COMPARISON WITH EXPERIMENTAL SPECTRA

A high-level ab initio theoretical study has been performed on the spe ctra and bond energies of pernitric acid, HO2NO2. Excellent agreement with experimental rotational constants, N-15 NMR chemical shifts, HO2 + NO2 reaction enthalpy, and vibrational frequencies are obtained. Sli ght revisions of low-frequency normal modes have been made. Vertical e xcitations are computed by CASPT2 for comparison with future high-reso lution UV-visible spectra and match the low resolution UV-visible spec tra of pernitric acid in solution. The optimized geometries reported a re superior to previous microwave structures because assumptions of bo nd lengths and angles from the analogous nitric acid and hydrogen pero xide molecules introduce significant errors.