Structures of catechol(H2O)1,3 clusters in the S0 and D0 states

Abstract

The structures of neutral catechol, catechol(H₂O)₁, and catechol(H₂O)₃ are investigated by IR/R2PI spectroscopy and ab initio calculations at the HF and MP2 level of theory. Furthermore, the structure of the ionic catechol(H₂O)₁⁺ cluster is derived from resonant IR-photodissociation spectroscopy as well as ab initio calculations. Trans-linear arrangements are obtained for the neutral (S₀) and ionic (D₀) ground state of the catechol(H₂O)₁ cluster. In the case of the neutral catechol(H₂O)₃ cluster (S₀ state) a cyclic and a π-bonded structure are discussed which are of similar stability. From the IR spectrum of catechol(H₂O)₃ it can be derived that the cyclic structure is the most probable arrangement. The calculated OH stretching frequencies of this structure are in good agreement with the experimentally observed values.