Electronically Excited States of XOONO (X = Cl, Br): Theoretical Studies

Antonija Lesar (1) , Milan Hodoscek (2)

1 Physical and Organic Chemistry
2 KI - National Institute of Chemistry [Llubljana]

Vertical electronic excitation energies of ClOONO and BrOONO, molecules relevant to atmospheric chemistry, were studied using ab initio multireference configuration interaction (MRD-CI) method with the cc-pVDZ and cc-pVTZ basis sets enlarged by s(N) and p(Cl/Br) long-range functions. The dominant transitions in the electronic spectra of ClOONO and BrOONO are calculated at 5.98 eV and 5.19 eV, respectively, with strong intensity and at 5.18 eV and 4.42 eV, respectively, with moderate intensity. Both transitions show multi-reference character, corresponding to linear combinations of the n(O) → π^* (N-O) type and n(O), σ^*(Cl/Br-O) → π^* (N-O) charge transfer type transitions. Thus, the transitions in the chlorine analogue lie about 0.8 eV higher in energy than in the bromine compound, i. e., the transitions are red-shifted by 32 nm and 42 nm, respectively, from ClOONO upon replacement of chlorine by bromine. The HOMO → LUMO transition can be considered as a n(Cl/Br) → σ^*(O-Cl/Br) type and is less intense.

Mots clés: Physical Sciences

Antonija Lesar, Milan Hodoscek. Electronically Excited States of XOONO (X = Cl, Br): Theoretical Studies. Molecular Physics, 2009, 107 (07), pp.693-700. ⟨10.1080/00268970902865485⟩. ⟨hal-00513276⟩