  from pyscf import gto, scf, cc

# Create a supercell composed of replicated units
mol = gto.M(
    atom='H 0.5 0.5 0.5; H 0.5 0.5 1.5; H 0.5 1.5 0.5; H 0.5 1.5 1.5; H 1.5 0.5 0.5; H 1.5 0.5 1.5; H 1.5 1.5 0.5; H 1.5 1.5 1.5',
    basis='gth-szv',
    symmetry=True,
    unit='B',
    verbose=0
)

# Run a molecular Hartree-Fock program using integrals between periodic Gaussians
mf = scf.RHF(mol)
mf.kernel()

# Call a molecular CC method for gamma point calculation
cc_gamma = cc.CCSD(mf)
cc_gamma.kernel()

# Perform k-point calculations for the same system
kpts = cc.gen_gp_kpts(mol, 4)
cc_kpts = cc.CCSD(mf)
cc_kpts.kernel(kpts)

# Calculate the differences between gamma/k-point mean-field, ccsd, ip-eomccsd, and ea-eomccsd calculations
diff_mf = cc_gamma.mo_energy - cc_kpts.mo_energy
diff_ccsd = cc_gamma.ccsd_energy - cc_kpts.ccsd_energy
diff_ip_eomccsd = cc_gamma.ip_eomccsd_energy - cc_kpts.ip_eomccsd_energy
diff_ea_eomccsd = cc_gamma.ea_eomccsd_energy - cc_kpts.ea_eomccsd_energy

# Print the differences
print('Differences between gamma/k-point mean-field, ccsd, ip-eomccsd, and ea-eomccsd calculations:')
print('  Mean-field:', diff_mf)
print('  CCSD:', diff_ccsd)
print('  IP-EOM-CCSD:', diff_ip_eomccsd)
print('  EA-EOM-CCSD:', diff_ea_eomccsd)