set basis cc-pvtz
molecule He2{
symmetry c1
0 1
    He 0.0 0.0 0.0
    He 0.0 0.0 XXXXX
}

set restricted_docc [0]
set active [4]

set calc_s_squared true
set S 0

set num_roots 3
set avg_states [0,1,2]

energy('CASSCF')