Improved First Ionization Potential of the Dimethylsilaethylene Molecule Obtained with High-Temperature Photoelectron Spectroscopy

Article abstract of DOI:10.1021/j100212a022

The vacuum-ultraviolet photoelectron spectrum of the pyrolysis products of 1,1-dimethyl-1-silacyclobutane (DMSCB) has been recorded.The band associated with the first ionization potential of the 1,1-dimethyl-1-silaethylene (DMSE) molecule has been observed with vertical and adiabatic ionization potentials of 7.98+/-0.01 eV and 7.71+/-0.03 eV, respectively.Analysis of the observed vibrational structure in this band gave ω_e = 760+/-30 cm^-1 and this is assigned to excitation of the H2C-Si< stretching mode in the ion.The experimental adiabatic ionization energy allows a lower limit for the heat of formation of (Me2Si=CH2)⁺ to be derived as 745+/-11 kJ mol^-1.