RHF interpretation: The desired spin-state is an octet: the state with component of spin MS = 7/2 and spin S = 7/2. In order to define this type of calculation other keywords must also be used. For a 'simple' octet calculation, use C.I.=7. When the configuration interaction calculation is done, all microstates having a component of spin, MS, equal to 7/2 are selected. These microstates are then used in the construction of states. Because of the way in which the microstates were chosen, only states of spin equal to, or greater than 7/2, can be constructed. From this set, only an octet state can be selected, all other states will be ignored. If ROOT=n is present, then the n'th octet state will be selected: otherwise the first octet state will be chosen. If several octets are to be calculated, say the second or third, then C.I.(n1,n2) should be used.

See also MS=n, SINGLET, DOUBLET, TRIPLET, QUARTET, QUINTET, SEXTET, SEPTET, and NONET. UHF interpretation: The system will have seven more alpha electrons than beta electrons.