pymatgen.io.nwchem module¶

class
NwInput
(mol, tasks, directives=None, geometry_options=(u’units’, u’angstroms’), symmetry_options=None, memory_options=None)[source]¶ Bases:
monty.json.MSONable
An object representing a Nwchem input file, which is essentially a list of tasks on a particular molecule.
Parameters:  mol – Input molecule. If molecule is a single string, it is used as a direct input to the geometry section of the Gaussian input file.
 tasks – List of NwTasks.
 directives – List of root level directives as tuple. E.g., [(“start”, “water”), (“print”, “high”)]
 geometry_options – Additional list of options to be supplied to the geometry. E.g., [“units”, “angstroms”, “noautoz”]. Defaults to (“units”, “angstroms”).
 symmetry_options – Addition list of option to be supplied to the symmetry. E.g. [“c1”] to turn off the symmetry
 memory_options – Memory controlling options. str. E.g “total 1000 mb stack 400 mb”

classmethod
from_file
(filename)[source]¶ Read an NwInput from a file. Currently tested to work with files generated from this class itself.
Parameters: filename – Filename to parse. Returns: NwInput object

classmethod
from_string
(string_input)[source]¶ Read an NwInput from a string. Currently tested to work with files generated from this class itself.
Parameters: string_input – string_input to parse. Returns: NwInput object

molecule
¶ Returns molecule associated with this GaussianInput.

class
NwOutput
(filename)[source]¶ Bases:
object
A Nwchem output file parser. Very basic for now  supports only dft and only parses energies and geometries. Please note that Nwchem typically outputs energies in either au or kJ/mol. All energies are converted to eV in the parser.
Parameters: filename – Filename to read. 
get_excitation_spectrum
(width=0.1, npoints=2000)[source]¶ Generate an excitation spectra from the singlet roots of TDDFT calculations.
Parameters:  width (float) – Width for Gaussian smearing.
 npoints (int) – Number of energy points. More points => smoother curve.
Returns:  (ExcitationSpectrum) which can be plotted using
pymatgen.vis.plotters.SpectrumPlotter.


class
NwTask
(charge, spin_multiplicity, basis_set, basis_set_option=u’cartesian’, title=None, theory=u’dft’, operation=u’optimize’, theory_directives=None, alternate_directives=None)[source]¶ Bases:
monty.json.MSONable
Base task for Nwchem.
Very flexible arguments to support many types of potential setups. Users should use more friendly static methods unless they need the flexibility.
Parameters:  charge – Charge of the molecule. If None, charge on molecule is used. Defaults to None. This allows the input file to be set a charge independently from the molecule itself.
 spin_multiplicity – Spin multiplicity of molecule. Defaults to None, which means that the spin multiplicity is set to 1 if the molecule has no unpaired electrons and to 2 if there are unpaired electrons.
 basis_set – The basis set used for the task as a dict. E.g., {“C”: “6311++G**”, “H”: “631++G**”}.
 basis_set_option – cartesian (default)  spherical,
 title – Title for the task. Defaults to None, which means a title based on the theory and operation of the task is autogenerated.
 theory – The theory used for the task. Defaults to “dft”.
 operation – The operation for the task. Defaults to “optimize”.
 theory_directives – A dict of theory directives. For example, if you are running dft calculations, you may specify the exchange correlation functional using {“xc”: “b3lyp”}.
 alternate_directives – A dict of alternate directives. For example, to perform cosmo calculations and dielectric constant of 78, you’d supply {‘cosmo’: {“dielectric”: 78}}.

classmethod
dft_task
(mol, xc=u’b3lyp’, **kwargs)[source]¶ A class method for quickly creating DFT tasks with optional cosmo parameter .
Parameters:  mol – Input molecule
 xc – Exchange correlation to use.
 **kwargs – Any of the other kwargs supported by NwTask. Note the theory is always “dft” for a dft task.

classmethod
esp_task
(mol, **kwargs)[source]¶ A class method for quickly creating ESP tasks with RESP charge fitting.
Parameters:  mol – Input molecule
 **kwargs – Any of the other kwargs supported by NwTask. Note the theory is always “dft” for a dft task.

classmethod
from_molecule
(mol, theory, charge=None, spin_multiplicity=None, basis_set=u‘631g’, basis_set_option=u’cartesian’, title=None, operation=u’optimize’, theory_directives=None, alternate_directives=None)[source]¶ Very flexible arguments to support many types of potential setups. Users should use more friendly static methods unless they need the flexibility.
Parameters:  mol – Input molecule
 charge – Charge of the molecule. If None, charge on molecule is used. Defaults to None. This allows the input file to be set a charge independently from the molecule itself.
 spin_multiplicity – Spin multiplicity of molecule. Defaults to None, which means that the spin multiplicity is set to 1 if the molecule has no unpaired electrons and to 2 if there are unpaired electrons.
 basis_set – The basis set to be used as string or a dict. E.g., {“C”: “6311++G**”, “H”: “631++G**”} or “631G”. If string, same basis set is used for all elements.
 basis_set_option – cartesian (default)  spherical,
 title – Title for the task. Defaults to None, which means a title based on the theory and operation of the task is autogenerated.
 theory – The theory used for the task. Defaults to “dft”.
 operation – The operation for the task. Defaults to “optimize”.
 theory_directives – A dict of theory directives. For example, if you are running dft calculations, you may specify the exchange correlation functional using {“xc”: “b3lyp”}.
 alternate_directives – A dict of alternate directives. For example, to perform cosmo calculations with DFT, you’d supply {‘cosmo’: “cosmo”}.

operations
= {u’‘: u’dummy’, u’frequencies’: u’Compute second derivatives and print out an analysis of molecular vibrations.’, u’energy’: u’Evaluate the single point energy.’, u’vscf’: u’Compute anharmonic contributions to the vibrational modes.’, u’freq’: u’Same as frequencies.’, u’dynamics’: u’Perform classical molecular dynamics.’, u’hessian’: u’Compute second derivatives.’, u’saddle’: u’Conduct a search for a transition state (or saddle point).’, u’gradient’: u’Evaluate the derivative of the energy with respect to nuclear coordinates.’, u’optimize’: u’Minimize the energy by varying the molecular structure.’, u’thermodynamics’: u’Perform multiconfiguration thermodynamic integration using classical MD.’, u’property’: u’Calculate the properties for the wave function.’}¶

theories
= {u’md’: u’Classical molecular dynamics simulation’, u’ccsd(t)’: u’Coupledcluster linearized triples approximation’, u’ccsd’: u’Coupledcluster single and double excitations’, u’esp’: u’ESP’, u’dft’: u’DFT’, u’ccsd+t(ccsd)’: u’Fourth order triples contribution’, u’scf’: u’HartreeFock’, u’sodft’: u’SpinOrbit DFT’, u’selci’: u’Selected CI with perturbation correction’, u’band’: u’Pseudopotential planewave DFT for solids using NWPW’, u’direct_mp2’: u’MP2 using a fulldirect algorithm’, u’mp2’: u’MP2 using a semidirect algorithm’, u’g3gn’: u’some description’, u’tddft’: u’Time Dependent DFT’, u’rimp2’: u’MP2 using the RI approximation’, u’pspw’: u’Pseudopotential planewave DFT for molecules and insulating solids using NWPW’, u’mcscf’: u’Multiconfiguration SCF’, u’tce’: u’Tensor Contraction Engine’}¶