```python
from pyscf.pbc import gto, scf, cc, df
import numpy as np

cell = gto.Cell()
cell.atom = '''
C 0. 0. 0.
C 1.42 1.42 1.42
'''
cell.basis = 'gth-szv'
cell.a = np.eye(3) * 3.5668
cell.verbose = 5
cell.build()

kpts = cell.make_kpts([2, 2, 2])
kmf = scf.KRHF(cell, kpts).run()

mycc = cc.KRCCSD(kmf)
mycc.kernel()

mycc_ip = cc.KRIP(mycc)
mycc_ip.kernel()

mycc_ea = cc.KREA(mycc)
mycc_ea.kernel()

mf_gamma = scf.RHF(cell).run()
cc_gamma = cc.CCSD(mf_gamma).run()

print("Mean-field energy difference (gamma/k-point):", np.abs(mf_gamma.e_tot - kmf.e_tot))
print("CCSD energy difference (gamma/k-point):", np.abs(cc_gamma.e_tot - mycc.e_tot))
print("IP-EOMCCSD energy difference (gamma/k-point):", np.abs(mycc_ip.e_tot - mycc.e_tot))
print("EA-EOMCCSD energy difference (gamma/k-point):", np.abs(mycc_ea.e_tot - mycc.e_tot))
```