Excitation energies can also be calculated using the Configuration-Interaction Singles (CIS) method. By default, singlet excited states are calculated. Triplet excited states can be obtained by setting triplet=1 in EOM card. This method cannot be expected to give accurate results, but can be used for quite large molecules. The states to be computed are specified as in EOM. Setting trans=1 switches on the calculation of one-electron properties. By default, dipole moments are calculated. Other required properties can be specified using EXPEC card. Dipole transition moments are also calculated.
hf cis,-3.1,1.2,trans=1