Q. Number of solutions in the SAC-CI optimization

 

A. Users can calculate other excited states in the SAC-CI goemetry optimization. The reference states in the perturbation selection are chosen by referring to the requested number of solutions. For example, following input calculates three roots for symmetry 3 and the geometry optimization is done for the second state. In this case, operators are selected with the three reference states.

 

#SAC-CI=(Triplet=(NState=(0,0,3,0)),

TargetState=(SpinState=Triplet, Symmetry=3, Root=2))/D95 Opt

 

  When users are interested in only the optimized state, it is efficient to specify the mimimum number of solutions; namely, in the above case, Triplet=(NState=(0,0,2,0)).

  With the input of Triplet=(NState=2), users can calculates other space symmetry like A₁, A₂, and B₂ states in C_2v group.