pyscf_ccpvtz_adc3.py

#!/usr/bin/env python3
## vi: tabstop=4 shiftwidth=4 softtabstop=4 expandtab
import adcc

from pyscf import gto, scf
from matplotlib import pyplot as plt

# Run SCF in pyscf
mol = gto.M(
    atom='O 0 0 0;'
         'H 0 0 1.795239827225189;'
         'H 1.693194615993441 0 -0.599043184453037',
    basis='cc-pvtz',
    unit="Bohr"
)
scfres = scf.RHF(mol)
scfres.conv_tol = 1e-13
scfres.kernel()

print(adcc.banner())

# Run an adc3 calculation:
singlets = adcc.adc3(scfres, n_singlets=3)
triplets = adcc.adc3(singlets.matrix, n_triplets=3)

print(singlets.describe())
print()
print(triplets.describe())

singlets.plot_spectrum()
plt.show()