x2c.rst

:mod:`x2c` --- exact-two-component approach

An example to apply scalar relativistic effects by decorating the scf object with module :mod:`x2c` is shown as following:

from pyscf import gto
from pyscf import scf
mol = gto.M(
    verbose = 0,
    atom = '''8  0  0.     0
              1  0  -0.757 0.587
              1  0  0.757  0.587''',
    basis = 'ccpvdz',
)
mf = scf.RHF(mol).x2c().run()
mol.spin = 1
mol.charge = 1
mol.build(0, 0)
mf = scf.UKS(mol).x2c1e()
energy = mf.kernel()

More examples can be find here:

Examples

• :source:`examples/x2c/01-spin_free_x2c.py`
• :source:`examples/x2c/02-basis_for_x.py`
• :source:`examples/x2c/10-picture_change.py`

Program reference

.. automodule:: pyscf.x2c

X2C

.. automodule:: pyscf.x2c.x2c
   :members:

1e spin-free x2c

.. automodule:: pyscf.x2c.sfx2c1e
   :members:

1e spin-free x2c gradient

.. automodule:: pyscf.x2c.sfx2c1e_grad
   :members:

1e spin-free x2c hessian

.. automodule:: pyscf.x2c.sfx2c1e_hess
   :members: