def get_potential_energy(self, atoms, force_consistent=False, dft_d_cutoff_radius=30.0):
"""
Altered version of the original get_potential_energy function
in the class Vasp. The function obtains the DFT energy by using
the original call for the VASP package and adds the DFT-D3 contribution
to the converged SCF-energy.
"""
# self.update(atoms)
# Conversion factors a.u. -> eV
Eh__2__eV = 27.211396132
#
# Get functional name as string
functional = xc_name(str.lower(vasp.Vasp.get_xc_functional(self)))
#
# Calling original VASP-calculator for energy
self.energy_free_or_zero = vasp.Vasp.get_potential_energy(self, atoms, force_consistent)
#
# Call DFT-D module: Energy and gradients
self.dispersion_correction, self.dft_d_gradient_contribution = d3_pbc(atoms, functional)
#
# Convert to proper units
self.dispersion_correction = self.dispersion_correction * Eh__2__eV
#
# Print out components (Useful?)
print >> sys.stdout, " "
print >> sys.stdout, "DFT total energy : ", self.energy_free_or_zero
print >> sys.stdout, "DFT-D3 correction : ", self.dispersion_correction
print >> sys.stdout, " "
print >> sys.stdout, "DFT-D3 final corrected energy: ", self.energy_free_or_zero + self.dispersion_correction
print >> sys.stdout, " "
#
# Adding correction contribution to energy
return self.energy_free_or_zero + self.dispersion_correction
def get_forces(self, atoms, dft_d_cutoff_radius=30.0):
"""
Altered version of the original get_forces function in the Vasp-class.
The function obtains the DFT forces by using the original call for the
VASP package and adds the DFT-D2 contribution to the calculated forces.
"""
self.update(atoms)
# Conversion factors a.u. -> eV and a.u. -> eV/Angst
Eh__2__eV = 27.211396132
Eh_rb__2__eV_Angst = 51.422086162
#
# Get functional name as string
functional = xc_name(str.lower(vasp.Vasp.get_xc_functional(self)))
#
# Calling original VASP-calculator for forces
self.dft_forces = vasp.Vasp.get_forces(self, atoms)
#
# Call DFT-D module: Energy and gradients
self.dispersion_correction, self.dft_d_gradient_contribution = d2_pbc(atoms, functional)
#
# Convert to proper units
self.dispersion_correction = self.dispersion_correction * Eh__2__eV
self.dft_d_gradient_contribution = self.dft_d_gradient_contribution * Eh_rb__2__eV_Angst
#
print
print "DFT-D total gradients:", -self.dft_d_gradient_contribution[0] + self.forces[0]
for ind_i in range(1, len(self.forces)):
print " ", -self.dft_d_gradient_contribution[ind_i] + self.forces[ind_i]
print
#
# Adding correction contributions to forces
# Note the (-) sign: DFT-D module delivers gradients, not forces
return self.dft_forces - self.dft_d_gradient_contribution
def get_forces(self, atoms):
"""
Altered version of the original get_forces function in the GPAW-class.
The function obtains the DFT forces by using the original call for the
GPAW package and adds the DFT-D contribution to the calculated forces.
"""
#
# Conversion factors a.u. -> eV and a.u. -> eV/Angst
Eh__2__eV = 27.211396132
Eh_rb__2__eV_Angst = 51.422086162
#
# Calling original VASP-calculator for forces
self.dft_forces = GPAW.get_forces(self, atoms)
#
# Get functional name as string
self.functional = xc_name(str.lower(GPAW.get_xc_functional(self)))
#
# Call DFT-D module: Energy and gradients
self.dispersion_correction, self.dft_d_gradient_contribution = d2_pbc(atoms,self.functional)
#
# Convert to proper units
self.dispersion_correction = self.dispersion_correction * Eh__2__eV
self.dft_d_gradient_contribution = self.dft_d_gradient_contribution * Eh_rb__2__eV_Angst
#
# Adding correction contributions to forces
# Note the (-) sign: DFT-D module delivers gradients, not forces
return self.dft_forces - self.dft_d_gradient_contribution
def get_potential_energy(self, atoms, force_consistent=False):
"""
Altered version of the original get_potential_energy function
in the class GPAW. The function obtains the DFT energy by using
the original call for the GPAW package and adds the DFT-D3 contribution
to the converged SCF-energy.
"""
#
# Conversion factors a.u. -> eV
Eh__2__eV = 27.211396132
#
# Calling original GPAW-calculator for energy
self.ks_scf_energy = GPAW.get_potential_energy(self, atoms, force_consistent)
#
# Get functional name as string
self.functional = xc_name(str.lower(GPAW.get_xc_functional(self)))
#
# Call DFT-D module: Energy and gradients
self.dispersion_correction, self.dft_d_gradient_contribution = d3_pbc(atoms, self.functional)
#
# Convert to proper units
self.dispersion_correction = self.dispersion_correction * Eh__2__eV
#
# # Print out components (Useful?)
# print
# print 'DFT total energy : ', self.ks_scf_energy
# print 'DFT-D3 correction : ', self.dispersion_correction
# print
# print 'DFT-D3 final corrected energy: ', self.ks_scf_energy + self.dispersion_correction
# print
#
# Adding correction contribution to energy
return self.ks_scf_energy + self.dispersion_correction
def get_dispersion_correction(self, atoms):
"""
Returns the DFT-D dispersion correction for the current geometry
"""
#
# Conversion factors a.u. -> eV
Eh__2__eV = 27.211396132
#
# Get functional name as string
self.functional = xc_name(str.lower(GPAW.get_xc_functional(self)))
#
# Call DFT-D module: Energy and gradients
self.dispersion_correction, self.dft_d_gradient_contribution = d2_pbc(atoms, self.functional)
#
# Convert to proper units
self.dispersion_correction = self.dispersion_correction * Eh__2__eV
#
#
# Return dispersion correction
return self.dispersion_correction
