psi4-data 1:1.1-5 / usr / share / psi4 / samples / opt11 / input.dat

#! Transition-state optimizations of HOOH to both torsional transition states.

# Optimization to 180 degree torsion from 120
molecule hooh {
 0 1
 H
 O 1 0.95
 O 2 1.40 1 105.0
 H 3 0.95 2 105.0 1 120.0
 noreorient
}
set {
  basis cc-pvdz
  opt_type ts
  docc = [ 5 , 4 ]
  intrafrag_step_limit 0.1
  # loose convergence criteria due to scf convergence problems as c2h structure is approached
  MAX_FORCE_G_CONVERGENCE 5.0e-4
}

thisenergy = optimize('scf')

# Optimization to 0 degree torsion from 100
molecule hooh {
 H
 O 1 0.95
 O 2 1.40 1 105.0
 H 3 0.95 2 105.0 1 100.0
}

thisenergy = optimize('scf')