# AO_BASIS

> Controls whether to avoid the AO->MO transformation of the two-electron integrals for the four-virtual case (<VV||VV>) by computing the corresponding terms in the AO basis. AO_BASIS = DISK algorithm reduces the memory requirements and can significantly reduce the cost of the energy computation if SIMULTANEOUS algorithm is used. For the TWOSTEP algorithm, however, AO_BASIS = DISK option is not recommended due to extra I/O.

> - Type: string
> - Possible Values: NONE, DISK
> - Default: DISK