Gauge-including atomic orbitals chemical shift shielding calculation

Another theoretical method, extensively exploited in chemical shift shielding calculation is gauge-including atomic orbitals (GIAO) [177] approach. That technique provides reasonable chemical shifts values for various nuclei. It should be noted that this approach does not take into account the periodicity of the crystal lattice and calculations are carried out for isolated molecules (gas phase). If analysis of intermolecular interactions is target of the project or there is its important part, then arbitrarily constructed cluster model has to be built up. 

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