is the effect of the additional diffuse higher angular momentum functions, evaluated as the difference in the EA with the aVnZ-F12 orbital basis compared to the analogous VnZ-F12 basis. Unsurprisingly, the additional diffuse functions always produce EAs that are closer to CBS estimates, and the general trend is that the effect of the diffuse functions is largest at the DZ level, reduces through TZ, and is smallest at QZ. However, for the 6p elements Tl-At, the effect is slightly larger at the TZ level than at DZ or QZ. In all cases the EA converges rapidly towards the estimated CBS limit, with the difference between aVQZ-F12 and CBS in the range of 0.02 -0.06 kcal mol -1 per correlated electron.