Abstract
A method for the computation of nuclear magnetic resonance (NMR) shieldings with second-order Møller-Plesset perturbation theory (MP2) is presented which allows to efficiently compute the entire set of shieldings for a given molecular structure. The equations are derived using Laplace-transformed atomic orbital second-order Møller-Plesset perturbation theory as a starting point. The Z-vector approach is employed for minimizing the number of coupled-perturbed self-consistent-field equations that need to be solved. In addition, the method uses the resolution-of-the-identity approximation with an attenuated Coulomb metric and Cholesky decomposition of pseudo-density matrices. The sparsity in the three-center integrals is exploited with sparse linear algebra approaches, leading to reduced computational cost and memory demands. Test calculations show that the deviations from NMR shifts obtained with canonical MP2 are small if appropriate thresholds are used. The performance of the method is illustrated in calculations on DNA strands and on glycine chains with up to 283 atoms and 2864 basis functions.
Highlights
Nuclear magnetic resonance (NMR) is a widely used spectroscopic method in the field of chemistry
In order to analyze the influence of the employed approximations on the accuracy, NMR shieldings were computed for all complexes/dimers from the S22 test set78 and for all structures from the benchmark set used by Flaig et al
We presented an efficient method for computing NMR shieldings at the MP2 level of theory, which is based on Laplacetransformed atomic-orbital MP2 (AO-MP2)
Summary
Nuclear magnetic resonance (NMR) is a widely used spectroscopic method in the field of chemistry. NMR spectra are highly sensitive to the molecular geometry and contain a wealth of structural information. Especially for large molecules, their interpretation can be difficult, and it can be challenging to unambiguously assign a molecular structure to a given spectrum. In such situations, the comparison with theoretically computed spectra can be very helpful. The comparison with theoretically computed spectra can be very helpful For this reason, much work has been done on the development of quantum-chemical methods for the simulation of NMR shieldings Much work has been done on the development of quantum-chemical methods for the simulation of NMR shieldings (for reviews, see, e.g., Refs. 1–3)
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