Comparison to related functionality in the ADF package

The ADF package contains already other possibilities to calculate NMR properties and ESR (EPR) properties, namely the stand-alone NMR program and the ESR option within the ADF program.

The stand-alone NMR program calculates the NMR shielding tensors of closed-shell molecules not only for the non-relativistic and scalar relativistic Pauli Hamiltonian, but also for the spin-orbit coupled Pauli Hamiltonian and scalar relativistic and spin-orbit coupled ZORA Hamiltonian, using a TAPE21 from a self-consistent ADF calculation. Only in the spin-orbit coupled cases the ADF calculation should use 'SYMMETRY NOSYM' (See ADF user's guide). However, the analysis of the different orbital contributions to the shielding tensor can be done much more extensively in the EPR/NMR program described here.

The ESR option within the ADF program can calculate the EPR g-tensor if spin-orbit coupling is included, either at the Pauli or ZORA level. If the calculation is spin-restricted there must be exactly one unpaired electron, which means it can then calculate only low spin g-tensors, with an effective spin of 1/2. If the calculation is spin unrestricted the collinear approximation must be used. There may be more than one unpaired electron, which means that one can calculate high-spin g-tensors. The EPR/NMR program can also calculate the g-tensor at the unrestricted level, and can also calculate high-spin g-tensors.

With the ADF program it is also possible to calculate more EPR parameters, namely the nuclear magnetic dipole hyperfine interaction (A-tensor) and the nuclear electric quadrupole hyperfine interaction (Q-tensor), see the ADF user guide and the keywords ESR and QTENS, respectively.