Before starting any energy calculations, MOLPRO checks if the one-and two-electron integrals are available for the current basis set and geometry and automatically computes them if necessary. It is therefore not necessary any more to call the integral program explicitly, as was done in older MOLPRO versions using the INT command. The program also recognizes automatically if only the nuclear charges have been changed, as is the case in counterpoise calculations. In this case, the two-electron integrals are not recomputed.
Before any energy calculation, the geometry and basis set must be defined in GEOMETRY and BASIS blocks, respectively.