We report isotope shifts of the no-phonon lines of V-Si+H/D complexes observed in low temperature photoluminescence spectra of proton/deuteron implanted and annealed samples showing both the hydrogen and deuterium spectra. We propose that the isotope shift of the no phonon lines is related to the zero-point energies of the vibrations in both the electronic ground and excited states of the complex. The red shift of the deuterium no phonon line with respect to the hydrogen line is consistent with a stiffer spring constant for the potential well associated with the excited state. We tentatively assign a weak shoulder on the H-3(s) first harmonic line to the C-13 isotope.