Hydrogen bonding between chlorine oxide and water (H2O · ClO) radical complex

Density functional theory was used to study the hydrogen bonding between the water and the ClO radical. The two energetically low-lying minima are 5 (2A′) and 6 (2A″), with hydrogen bonding occurring between the chlorine atom in the ClO radical and the hydrogen atom in the water; the 2A′ state has a slightly (∼0.3 kcal/mol) lower energy. Another hydrogen bond occurs between one of the hydrogen atom in the water and oxygen atom in the ClO radical. The optimized geometry parameters, rotational constants and interaction energies for various isomers were calculated at the UB3LYP and UMP2 levels. The infrared spectra and the vibrational frequency shifts are also reported.