***,OH
include procedures
geometry={O;H,O,1.83}     ! Geometry definition
set,symmetry=[2,3,1],spin=1   ! 2Pix, 2Piy, and 2Sigma+ states
occ=[4,2,2]               ! 4 sigma and 2 pi occupied
runcas                    ! SA-CASSCF for all three states
set,symmetry=[2,1]            ! remove Piy
runmrci                   ! MRCI for 2Pix and 2Sigma+