The singlet states of SiO that correlate with ground state atoms have been studied. The computed spectroscopic constants are in good agreement with experiment. The lifetime of the E state has been calculated to be 10.9 ns; this is larger than the results of previous computations and is in excellent agreement with the experimental value of 10.5 +/- 1.1 ns. The lifetime of the A state is about three times larger than found in experiment. We suggest that absorption from the X state to the (2)(1)Pi state is responsible for the unidentified lines in the experiment of Hormes et al. Published by Elsevier B.V.