Theoretical study of energies, structures, and vibrational spectra of the carbonic acid–hydroperoxy radical complexes

In this work, we present the results for the first time of our study on hydrogen‐bonded H 2 CO 3 –HO 2 complexes (structures 1, 2) by means of ab initio molecular orbital theory. These complexes are important intermediates in the reaction of the hydroperoxy radical and cabonic acid. We calculated that these structures are a six‐membered ring. We found that the binding energy of two complexes are 5.8 and 9.3 kcal/mol using the CCSD(T) method. We also calculated the vibrational and rotational frequencies for these complexes. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005