Polarization propagators: A powerful theoretical tool for a deeper understanding of NMR spectroscopic parameters

Theoretical study of the nuclear spin-molecular rotation coupling for relativistic electrons and non-relativistic nuclei

“…The term of the relativistic RSPT expression of E (2) involving positronic states is now considered. Taking into account that within the QED picture, negative energy solutions of the Dirac equation are re-interpreted as positive energy states for positrons, 29,31 the non-relativistic and lower order contributions to E b , Eq.…”

“…In the last decade, powerful relativistic quantum chemistry tools were developed to obtain the nuclear magnetic shielding and spin-spin coupling tensors in a relativistic framework. [1][2][3] In fact, relativistic effects have shown to have deep influence even in qualitative aspects of NMR spectra, as shown, e.g., in the remarkable Xe spectrum discussed in Ref. 4. However, the relation between theoretical and experimental values of the NMR nuclear magnetic shielding can only be established for the relative shielding of a same nucleus in different chemical environments, i.e., the chemical shift.…”

Perspective: Relativistic effects

“…178,179 For additional examples and broader coverage of the literature on relativistic NMR and EPR calculations the reader is referred to some of the available reviews. 21,169,170,[180][181][182] Another property that plays a role in EPR and other spectroscopic techniques for paramagnetic molecules (e.g., magnetocircular dichroism) is the zero-field splitting. There have been important recent advances regarding the calculation of this property; see Schmitt et al 183 and references therein.…”

Relativistic calculations of magnetic resonance parameters: background and some recent developments

“…For references to older literature, the review articles cited in the Introduction are recommended (among the author's publications see references [9,26,27]). Reviews covering NMR and EPR calculations can also be found in earlier studies [161][162][163][164][165][166][167]. The articles cited in the following subsections of course also contain relevant references to prior art.…”

“…Aucar et al [163] have put forward a relativistic theory for polarization propagators as a framework for correlated relativistic calculations of NMR shielding and J-coupling. The three lowest levels of the approach have been designated as PZOA (pure zeroth-order approximation), FOPPA (first-order polarization propagator approximation) or RPA (random phase approximation), and SOPPA (second-order polarization propagator approximation).…”