The difference between functionals (∆ HSE06 ) is shown in Figure . The SVWN5 results are significantly larger than those obtained with HSE06. For the molecular case, QZ values are twice as large with the pure functional than with the hybrid, and thrice as large with aTZ and aQZ. For the periodic calculations, this difference increases to a factor of three and four for QZ and aTZ, respectively, but it decreases to a factor of two for aQZ. The change from molecular to periodic cases is likely due to intermolecular interactions. However, the different behavior across basis sets may be another indication that diffuse functions may be problematic for PBC calculations. In any case, the choice of functional seems to have the largest impact on the calculated values, followed by the choice of basis set, and to a much smaller degree by the choice of gauge.