Richard Dawes, Bin Jiang and Hua Guo, UV absorption spectrum and photodissociation channels of the simplest Criegee intermediate (CH2OO), J. Amer. Chem. Soc. 137, 50 (2015).

 

ABSTRACT: The singlet states of the simplest Criegee interme-diate (CH2OO) have been characterized along the O-O dissociation coordinate using explicitly-correlated MRCI-F12 electronic structure theory. It is found that a high-level treatment of dynamic electron-correlation is essential to accurately describe these states. We find a significant well on the B-state at the MRCI-F12 level with an equilibrium structure that differs substantially from that of the ground X-state. This well is presumably responsible for the apparent vibrational structure in some experimental UV absorption spectra, analogous to the structured Huggins band of the iso-electronic ozone. The B-state potential in the Franck-Condon region is sufficiently accurate that an absorption spectrum calculated with a one-dimensional model agrees remarkably well with experiment.