Running qc2-ASE calculators via qc2Data class

One of the key features of qc2Data is its ability to run qc2-ASE calculators on-the-fly. This is achieved by invoking its run() method.

An example is given below:

from ase.build import molecule
from qc2.ase import PySCF
from qc2.data import qc2Data

# set ASE Atoms object
mol = molecule('H2')

# instantiate qc2Data class
qc2data = qc2Data(
    molecule=mol,
    filename='h2.hdf5',
    schema='qcschema'
)

# attach a calculator to the molecule attribute
qc2data.molecule.calc = PySCF()

# run qc2-ASE calculator
qc2data.run()

Please note that, before invoking the run() method, it is necessary to attach a qc2-ASE calculator to qc2data.molecule via the ASE calc attribute. As described in Running stand-alone qc2-ASE calculations, we can attach any implemented calculator. run() will then execute the calculator and automatically save the relevant qchem data into h2.hdf5.

Important

If you intend to use qc2 in conjunction with ROSE, you should instantiate qc2Data with an empty molecule parameter [1]. Indeed, differently from standard ASE calculators, ROSE relies on custom dataclasses for reading molecular information and does not depend on information typically contained in ASE Atoms. See the example code below:

from qc2.ase import ROSE, ROSETargetMolecule, ROSEFragment
from qc2.data import qc2Data

# define ROSE target molecule and fragments
molecule = ROSETargetMolecule(...)
frag1 = ROSEFragment(...)
fragn = ROSEFragment(...)

# instantiate qc2Data - no Atoms() needed
qc2data = qc2Data(
    filename='ibo.fcidump',
    schema='fcidump'
)

# attach ROSE calculator to an empty Atoms()
qc2data.molecule.calc = ROSE(
    rose_calc_type='atom_frag',
    rose_target=molecule,
    rose_frags=[frag1, ..., fragn],
    rose_mo_calculator='pyscf'
)

# run ROSE calculator
qc2data.run()

Footnotes

[1]

If this is done, qc2Data automatically sets molecule to an empty Atoms() object.