Dissociative photoionization of dimethyl ether in the energy range of 13.3～14.3 eV

Dissociative photodissociation of dimethyl ether in the photon energy of 13.30～14.30 eV was studied using threshold photoelectron photoion coincidence mass spectrometry, combined with photoionization using a vacuum ultraviolet light source from synchrotron radiation. In this range, the dimethyl ether ions in B2B2 and C2A2 states were prepared, and the main fragment ions were m/z=45, 29 and 31. By subtracting the contribution of the m/z=29 fragment ions, the reliable time-of-flight profile of the m/z=31 fragment ions was obtained. Then the related kinetic energy distribution was derived from fitting the profile. Below 14.00 eV, a unique statistical dissociation was observed for the formation of the m/z=31 ions, while the dissociation mechanism was changed significantly to dual dissociation