direct vs. in-core calculations

 One other point that is worth making is that even if you are performing
 the calculation with the 5 pure d functions, gaussian is doing the integral
 calculation using the 6 cartesian d functions and then performing a
 transformation. The default number of d functions varies with the basis
 set, so 6-31G* uses the cartesian set by default while 6-311G* uses the
 pure set by default (has to do with how the basis set was originally
 generated). For a 6-311G** calculation on benzene, if you assume 5d, then
 you will come up with N=144 rather than N=150. This would put your projection
 at 54.5Mw rather than the actual 64.1Mw (a large difference).
 ||  Kevin Moore                      North Carolina Supercomputing Center   ||
 ||  Scientific Support Analyst       3021 Cornwallis Rd.                    ||
 ||  (919) 248-1179                   Research Triangle Park, NC 27709       ||