DOUBLET 

Description

For C.I. calculations, DOUBLET constrains the spin multiplicity of the primary CI eigenstate to be 2, i.e., a doublet, corresponding to 1 unpaired electron. For ROOT=n, the n^th lowest-energy doublet CI eigenstate will be the primary eigenstate.

See also:

C.I., ROOT, OPEN, SINGLET, TRIPLET, etc.