**Hamiltonians**

- non-relativistic one-component (1c) Hartree-Fock (HF) and Kohn-Sham (KS)
- relativistic 4c matrix/modified Dirac-Hartree-Fock (mDHF) and Dirac-Kohn-Sham (mDKS)
- scalable speed of light
- switchable spin-orbit interaction

Documentation on the relativistic calculation of Nuclear Magnetic Resonance (NMR) chemical shielding (CS) tensors.

**Hamiltonians**

- non-relativistic one-component (1c) Hartree-Fock (HF) and Kohn-Sham (KS)
- relativistic 4c matrix/modified Dirac-Hartree-Fock (mDHF) and Dirac-Kohn-Sham (mDKS)
- scalable speed of light
- switchable spin-orbit interaction

**DFT non-collinear functionals**

- local (SVWN5)
- GGA (PBE,BLYP,KT2,BP86,PP86)
- hybrid (PBE0,B3LYP)

**DFT non-collinear analytical kernels**

- full expressions including the GGA part
- adiabatic local density approximation (ALDA/XALDA)

**Reference (perturbation-free) wave function models**

- Kramers restricted determinant for closed-shell singlets
- Kramers unrestricted determinant for open-shell doublets

**Methods for solving the gauge origin problem**

- common gauge origin (CGO)
- gauge including atomic orbitals (GIAO), also known as London atomic orbitals (LAO)

**Nuclear charge distribution models**

- point
- finite Gaussian-type

**Nuclear magnetic moment distribution models**

- point

**Integral evaluation techniques**

- analytic with an in-built LAO phase factor
- analytic with an in-built restricted kinetic balanced (RKB) condition for the small-component
- analytic with an in-built restricted magnetic balanced (RMB) condition for the small-component
- one-center approximation for the SSSS-type electron repulsion integrals

**Perturbation theory-based spin-orbit contribution to the NMR shielding tensor (recommended for analysis)**

- << FC;SO,L >>
- << SD;SO,L >>

**Additional features**

- DIIS convergence acceleration
- molecular orbital analysis of the paramagnetic contribution
- parallel execution on shared-memory parallel architectures (SMPs)

**Approximations/Limitations**

- restart from a previous run is not implemented
- non-relativistic 1c Hamiltonians are only available for CGO method
- hybrid DFT functionals are only available for closed-shell singlets
- the calculation for open-shell doublets is only available with ALDA/XALDA DFT kernels
- full expression for analytical DFT kernels including the GGA part is only available for closed-shell singlets
- four-center two-electron integrals in the RMB basis are neglected in the framework of CGO

S. Komorovsky, M. Repisky, O. L. Malkina, V. G. Malkin, I. Malkin-Ondik, and M. Kaupp

A fully relativistic method for calculation of nuclear magnetic shielding tensors with a restricted magnetically balanced basis in the framework of the matrix Dirac-Kohn-Sham equation

*J. Chem. Phys.* **128**, 104101 (2008)

S. Komorovsky, M. Repisky, O. L. Malkina, and V. G. Malkin

Fully relativistic calculations of NMR shielding tensors using restricted magnetically balanced basis and gauge including atomic orbitals

*J. Chem. Phys.* **132**, 154101 (2010)

S. Komorovsky, M. Repisky, K. Ruud, O. L. Malkina, and V. G. Malkin

Four-component relativistic density functional theory calculations of NMR shielding tensors for paramagnetic systems

*J. Phys. Chem. A* **117**, 14209-14219 (2013)

M. Repisky, S. Komorovsky, R. Bast, and K. Ruud

Relativistic calculations of nuclear magnetic resonance parameters

*New Developments in NMR* , 267-303 (2016)

ReSpect 5.1.0 (2019), *relativistic spectroscopy DFT program of authors *

M. Repisky, S. Komorovsky, V. G. Malkin, O. L. Malkina, M. Kaupp, K. Ruud,
*with contributions from*
R. Bast, R. Di Remigio, U. Ekstrom, M. Kadek, S. Knecht, L. Konecny, E. Malkin, I. Malkin Ondik
(http://www.respectprogram.org)

November 7, 2019

Department of Chemistry

UiT The Arctic University of Norway

TromsÃ¸, NO-9037 Norway

Email: info@respectprogram.eu