ZORA

The ZORA equation is the zeroth order regular approximation to the Dirac equation, for some details see also ZORA details. The regular expansion, which leads to the ZORA Hamiltonian, remains valid even for a Coulombic potential. This is in contrast with the expansion that leads to the Pauli Hamiltonian, which is divergent for a Coulombic potential. A scalar relativistic Hamiltonian is a relativistic Hamiltonian without spin-orbit coupling.

ZORA can be included in ADF with the subkey ZORA of the key RELATIVISTIC. See also the ADF-GUI user documentation for: Model Hamiltonians.

• the ZORA Hamiltonian is bounded from below
• scaled ZORA spinor energies are exactly equal to Dirac energies for hydrogen like systems
• spin-orbit coupling can be taken into account
• all electron relativistic basis sets for all elements
• ZORA can be used for most spectroscopic properties
• scalar relativistic ZORA can be used for structure and reactivity

Links

ADF User Documentation: relativistic effects
ADF-GUI: model Hamiltonians
Examples: relativistic effects
References: ZORA
Related: spin-orbit coupling, ZORA details