The importance of nuclear magnetic resonance (NMR) spectroscopy for modern
chemistry and biochemistry cannot be overestimated. Since there is no direct
relationship between the measured NMR signals and structural properties, the
necessity for a reliable method to predict NMR chemical shifts arises and
despite tremendous progress in experimental techniques, the understanding and
reliable assignment of observed experimental spectra remains often a highly
difficult task. As such, quantum chemical methods can be extremely useful,
both in solution and in the solid
Phys. Chem. Chem. Phys.
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(2004), 116, pp. 4585.
Features of Q-Chem’s NMR package include:
Restricted Hartree-Fock and DFT calculations of NMR chemical shifts using gauge-including atomic orbitals.
Support of linear-scaling CFMM and LinK procedures (Section 4.6) to evaluate Coulomb- and exchange-like matrices.
Density matrix-based coupled-perturbed SCF approach for linear-scaling NMR calculations.
Support for basis sets up to functions.
Support for LDA, GGA, Meta-GGA
Chem. Phys. Lett.
(2004), 390, pp. 408. , global hybrid and common range-separated functionals (RSH only support s, p and d basis functions). VV10 is the only non-local correlation functional supported.
Calculation of NMR chemical shifts and indirect spin-spin couplings is discussed in Section 10.12.1. Additional magnetic properties can be computed, as described in Section 10.12.3. These include hyperfine interaction tensors (electron spin–nuclear spin interaction) and nuclear quadrupole interactions with electric field gradients.