This method keyword requests an excited state energy calculation using the ZIndo/S method [Ridley73, Ridley76, Bacon79, Zerner80, Zerner82, Anderson86, Hanson87, Thompson91, Zerner91]. Note that ZIndo calculations must not specify a basis set keyword.
Singlets
Solve only for singlet excited states. Only effective for closed-shell systems, for which it is the default.
Triplets
Solve only for triplet excited states. Only effective for closed-shell systems.
50-50
Solve for half triplet and half singlet states. Only effective for closed-shell systems.
Root=N
Specifies the “state of interest”. The default is the first excited state (N=1).
NStates=M
Solve for M states (the default is 3). If 50-50 is requested, NStates gives the number of each type of state for which to solve (i.e., the default is 3 singlets and 3 triplets).
Add=N
Read converged states off the checkpoint file and solve for an additional N states.
Window=(m[,n])
The two values specify the starting and ending orbitals to be used. The default is to use all orbitals. A value of zero indicates the first or last orbital, depending on where it is used. If the value for the first orbital is negative (-m), then the highest m orbitals are retained; the value for the last orbital is negative (-n), then the highest n orbitals are frozen. If m is positive and n is omitted, n defaults to 0. If m is negative and n is omitted, then the highest |m| occupied and lowest |m| virtual orbitals are retained.
Energies only. The Density keyword is ignored for ZIndo calculations.
Last update: 23 April 2013