Abstract:

 The geometries and fundamental vibrational frequencies of trans-and C2v- nitrous acid have been determined by ab initio calculations at the MP2 level with 6-31G** and 6-311+G** basis sets. The calculation results satisfactorily reproduce the experimental structural and vibrational spectral features of trans-HONO. Calculations at the same levels indicate that the C2v-HNO2 is also a stable conformer of nitrous acid. The calculated frequencies of C2v-HNO2 are in good agreement with the matrix infrared spectral features.

Key words: Ab initio, Nitrous acid isomers, Vibrational frequecies