The equation-of-motion coupled cluster method is used to obtain a precise estimate of the lowest adiabatic singlet-singlet excitation energy(S-1<--S-0) of vinylidene. As photodetachment spectroscopy offers a promising means for producing the first excited singlet state, harmonic vibrational frequencies of S-1 and the extent of mixing between the corresponding normal modes and those of the anion are also calculated. To calibrate the calculations and provide a basis for empirical correction, parallel studies of the previously observed T-1 and T-2 triplet states are reported. The adiabatic excitation energy [S-1<--S-0] is estimated to be 3.12+/-0.05 eV, suggesting a photodetachment threshold energy of 3.61+/-0.05 eV. Progressions in the totally symmetric C-C stretch and H-C-H bending modes should be pronounced in the spectrum, with the extent of mode mixing similar to that found for the S-0<--anion and T-1<--anion processes, but differing in phase.