High-level ab initio studies of the electronic excited states of the hydroxyl radical and water-hydroxyl complex

摘要

The lowest-energy electronic transitions in the hydroxyl radical and the hydrogen bound complex H_2O centre dot HO have been studied using ab initio methods.We have used the complete active-space self-consistent field and multireference configuration interaction(MRCI)methods to calculate vertical excitation energies and oscillator strengths.At the MRCI level the lowest-lying 2SUM~+<-~2II electronic transition is redshifted by about 2500 cm~(-1)upon formation of the H_2O centre dot HO complex.We propose that this transition could be used to identify the complex in the gas phase,which in turn could be used to examine the role of H_2O centre dot HO in atmospheric reactions.