ORCA-ASE

ORCA-ASE interface

An ASE interface has been written that is now part of ASE. See ASE for details

ORCA-ASE examples

Some example ASE inputfiles that use the interface:

Geometry optimization with ORCA and ASE of H₂O:

# ORCA example
from ase.calculators.orca import ORCA
from ase.atoms import Atoms
from ase.optimize.lbfgs import LBFGS
hareV=27.211399
#ORCA interface does not use xc, basis etc.
#Instead 2 keywords: orcasimpleinput and orcablocks are used to specify
#the contents of the ORCA ! line in an ORCA inputfile and the block input.-
calc = ORCA(label='orca',
maxiter=2000,
charge=0, mult=1,task='gradient',
orcasimpleinput='PBE def2-SVP',
orcablocks='%scf Convergence verytight \n maxiter 300 end \n %pal nprocs 1 end'
)

#Geometry input. Either like this:
water = Atoms('OHH',
positions=[(0, 0, 0), (1, 0, 0), (0, 1, 0)],
calculator=calc)
# Or like this:
water=ase.io.read('water.xyz')
#e_water = water.get_potential_energy()
#print("water energy is", e_water)
#Optimization stuff
#energy(water)
opt = LBFGS(water)
opt.run(fmax=0.00005)
forces = water.get_forces()
energy = water.get_potential_energy()
positions = water.get_positions()

#
print("Final energy is", energy, "eV")
print("Final energy is", energy/hareV, "hartree")
print("All done, final positions are:")
print(positions)