OH overtone spectra and intensities of pernitric acid

The integrated absorption intensities of the 3νOH overtone transitions of the OH stretch of pernitric acid (HO2NO2) and nitric acid (HONO2) were measured in concentrated sulfuric acid (H2SO4) solution. As well, oscillator strengths for the OH overtones of isolated HO2NO2 were calculated ab initio. Both results indicate that the OH overtones of HO2NO2 have larger oscillator strengths than the corresponding transitions in HONO2 (1.3±0.5 times greater in H2SO4 solution; about 2 times greater according to the ab initio calculations). Overtone-induced photodissociation of HO2NO2 could play a role in HOx production at high solar zenith angles.