#! Mk-MRCCSD frequencies. $^1A@@1$ O$@@3$ state described using
#! the Ms = 0 component of the singlet.  Uses TCSCF orbitals.

test_freq.set(0,582.44)
test_freq.set(1,937.49)

memory 250 mb

molecule ch2 {
  0 1
            O    -2.1952205263  -0.0000000000   0.4671108832
            O     0.0000000000   0.0000000000  -0.9342217664
            O     2.1952205263   0.0000000000   0.4671108832

  units au
}

set {
  basis DZ
  e_convergence 13
  d_convergence 10
  r_convergence 9
}

set mcscf {
  reference       twocon
  docc            [6,0,4,1]      # Doubly occupied MOs
  socc            [0,1,0,1]      # Singly occupied MOs
  maxiter         300
}

set psimrcc {
  corr_wfn        ccsd         # Do Mk-MRCCSD 
  frozen_docc     [2,0,1,0]    # Frozen MOs
  restricted_docc [4,0,3,1]    # Doubly occupied MOs
  active          [0,1,0,1]    # Active MOs
  frozen_uocc     [0,0,0,0]    # Frozen virtual MOs
  corr_multp      1            # Select the Ms = 0 component
  wfn_sym         A1           # Select the A1 state
  tikhonow_omega 0.001         # Regularization of the c_mu/c_nu fractions to make sure we converge
}

freq('psimrcc')
