Dual-basis calculations are controlled with the following $rem. DUAL_BASIS_ENERGY turns on the dual-basis approximation. Note that use of BASIS2 without DUAL_BASIS_ENERGY only uses basis set projection to generate the initial guess and does not invoke the dual-basis approximation (see Section 4.4.5). OVPROJECTION is used as the default projection mechanism for dual-basis calculations; it is not recommended that this be changed. Specification of SCF variables (e.g., THRESH) will apply to calculations in both basis sets.