The parameter to this option is either a grid name keyword or a specific grid specification. Other grids may be selected by giving an integer value N as the argument to Grid. It is recommended for molecules containing lots of tetrahedral centers and for computing very low frequency modes of systems. Pass0Grid requests the obsolete Specific grids may be selected by giving an integer value N as the argument to Grid. If a larger number of angular points is desired, a spherical product grid can be used.
Large values are expensive.
Integral Format Option Raff Raff Requests that the Raffenetti format for the two-electron integrals be used. This is the default. NoRaff demands that the regular integral format be used. This affects conventional SCF and both conventional and direct frequency calculations. The default is BWeights, which uses the weighting scheme of Becke.