Vibrational contributions to vicinal proton–proton coupling constants3JHH

Esteban, Ángel L.; Galache, Maria P.; Fabián, J. San; Casanueva, Jorge; Contreras, Rubén H.

doi:10.1080/00268971003630687

Cited by 6 publications

(3 citation statements)

References 43 publications

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“…Recent reports have appeared in the literature on the development of SSCC‐scaled factors. In the present work, we optimize general shifting and/or scaling factors that can be used to obtain 1 J CH . These optimized factors are derived by correlating computed 1 J CH , which are obtained by applying 36 functional/basis set combinations over 68 organic molecules containing first and second row elements, with the corresponding experimental values.…”

Section: Introductionmentioning

confidence: 99%

Computational NMR coupling constants: Shifting and scaling factors for evaluating ¹J_CH

Fabián

Vega

Suardíaz

et al. 2013

Magnetic Reson in Chemistry

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Optimized shifting and/or scaling factors for calculating one-bond carbon-hydrogen spin-spin coupling constants have been determined for 35 combinations of representative functionals (PBE, B3LYP, B3P86, B97-2 and M06-L) and basis sets (TZVP, HIII-su3, EPR-III, aug-cc-pVTZ-J, ccJ-pVDZ, ccJ-pVTZ, ccJ-pVQZ, pcJ-2 and pcJ-3) using 68 organic molecular systems with 88 (1)JCH couplings including different types of hybridized carbon atoms. Density functional theory assessment for the determination of (1)JCH coupling constants is examined, comparing the computed and experimental values. The use of shifting constants for obtaining the calculated coupling improves substantially the results, and most models become qualitatively similar. Thus, for the whole set of couplings and for all approaches excluding those using the M06 functional, the root-mean-square deviations lie between 4.7 and 16.4 Hz and are reduced to 4-6.5 Hz when shifting constants are considered. Alternatively, when a specific rovibrational contribution of 5 Hz is subtracted from the experimental values, good results are obtained with PBE, B3P86 and B97-2 functionals in combination with HIII-su3, aug-cc-pVTZ-J and pcJ-2 basis sets.

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Section: Introductionmentioning

confidence: 99%

Computational NMR coupling constants: Shifting and scaling factors for evaluating ¹J_CH

Fabián

Vega

Suardíaz

et al. 2013

Magnetic Reson in Chemistry

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“…VPT2 offers an affordable solution for computing anharmonic effects by using the harmonic approximation as the basis for the zeroth-order Hamiltonian. Such a theory is capable of including temperature- and isotope-dependent corrections and has been applied many times, ,− but high-level vibrational corrections at the level of coupled cluster theory are rare. − In one of these studies, the authors employed and compared different levels of theory for the calculation of vibrational corrections.…”

Section: Introductionmentioning

confidence: 99%

Exploring Alternate Methods for the Calculation of High-Level Vibrational Corrections of NMR Spin–Spin Coupling Constants

Gleeson,

Aggelund,

Østergaard

et al. 2024

J. Chem. Theory Comput.

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Traditional nuclear magnetic resonance (NMR) calculations typically treat systems with a Born−Oppenheimer-derived electronic wave function that is solved for a fixed nuclear geometry. One can numerically account for this neglected nuclear motion by averaging over property values for all nuclear geometries with a vibrational wave function and adding this expectation value as a correction to an equilibrium geometry property value. Presented are benchmark coupled-cluster singles and doubles (CCSD) vibrational corrections to spin−spin coupling constants (SSCCs) computed at the level of vibrational second-order perturbation theory (VPT2) using the vibrational averaging driver of the CFOUR program. As CCSD calculations of vibrational corrections are very costly, cheaper electronic structure methods are explored via a newly developed Python vibrational averaging program within the Dalton Project. Namely, results obtained with the second-order polarization propagator approximation (SOPPA) and density functional theory (DFT) with the B3LYP and PBE0 exchange-correlation functionals are compared to the benchmark CCSD//CCSD(T) and experimental values. CCSD//CCSD(T) corrections are also combined with literature CC3 equilibrium geometry values to form the highest-order vibrationally corrected values available (i.e., CC3//CCSD(T) + CCSD//CCSD(T)). CCSD//CCSD(T) statistics showed favorable statistics in comparison to experimental values, albeit at an unfavorably high computational cost. A cheaper CCSD//CCSD(T) + B3LYP method showed quite similar mean absolute deviation (MAD) values as CCSD//CCSD(T), concluding that CCSD//CCSD(T) + B3LYP is optimal in terms of cost and accuracy. With reference to experimental values, a vibrational correction was not worth the cost for all of the other methods tested. Finally, deviation statistics showed that CC3//CCSD(T) + CCSD//CCSD(T) vibrational-corrected equilibrium values deteriorated in comparison to CCSD//CCSD(T) attributed to the use of a smaller basis set or lack of solvation effects for the CC3 equilibrium calculations.

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“…VPT2 offers an affordable solution for computing anharmonic effects using the harmonic approximation as the basis for the zero-order Hamiltonian. Such a theory is capable of includ-ing temperature and isotope-dependent corrections and has been applied many times, 1,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] but high-level vibrational corrections at the level of coupled cluster theory are rare. [29][30][31] In one of these studies, 31 the authors employed and compared different levels of theory for the calculation of vibrational corrections.…”

Section: Introductionmentioning

confidence: 99%

Exploring Alternate Methods to High-Level Vibrational Correction Calculations of NMR Spin-Spin Coupling Constants

Gleeson,

Aggelund,

Østergaard

et al. 2023

Preprint

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Traditional nuclear magnetic resonance (NMR) calculations typically treat systems with a Born-Op penheimer-derived electronic wavefunction that is solved for a fixed nuclear geometry. One can numerically account for this neglected nuclear motion by averaging over property values for all nuclear geometries with a vibrational wavefunction and adding this expectation value as a correction to an equilibrium property value. Presented are benchmark coupled-cluster singles and doubles (CCSD) vibrational corrections to spin-spin coupling constants (SSCCs) computed at the level of vibrational second-order perturbation theory (VPT2) using the vibrational averaging driver of the CFOUR program. As CCSD calculations of vibrational corrections are very costly, cheaper electronic structure methods are explored via a newly developed Python vibrational averaging program within the Dalton Project. Namely, the second-order polarisation propagator approximation (SOPPA) and density functional theory (DFT) with the B3LYP and PBE0 exchange-correlation functionals are compared to the benchmark CCSD//CCSD(T) and experimental values. CCSD//CCSD(T) corrections are also combined with literature CC3 equilibrium values to form the highest-order vibrationally corrected values available i.e. CC3//CCSD(T) + CCSD//CCSD(T). CCSD//CCSD(T) statistics showed favourable statistics in comparison to experimental values, albeit at an unfavourably high computational cost. A cheaper CCSD//CCSD(T) + B3LYP method showed quite similar mean absolute deviation (MAD) values as CCSD//CCSD(T), concluding that CCSD//CCSD(T) + B3LYP is optimal in terms of cost and accuracy. With reference to experimental values, a vibrational correction was not worth the cost for all other methods tested. Finally, deviation statistics showed that CC3//CCSD(T) + CCSD//CCSD(T) vibrational corrected equilibrium values deteriorated in comparison to CCSD//CCSD(T) attributed to the use of a smaller basis and/or lack of solvation effects for the CC3 equilibrium calculations.

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Vibrational contributions to vicinal proton–proton coupling constants³J_HH

Cited by 6 publications

References 43 publications

Computational NMR coupling constants: Shifting and scaling factors for evaluating ¹J_CH

Computational NMR coupling constants: Shifting and scaling factors for evaluating ¹J_CH

Exploring Alternate Methods for the Calculation of High-Level Vibrational Corrections of NMR Spin–Spin Coupling Constants

Exploring Alternate Methods to High-Level Vibrational Correction Calculations of NMR Spin-Spin Coupling Constants

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Vibrational contributions to vicinal proton–proton coupling constants3JHH

Cited by 6 publications

References 43 publications

Computational NMR coupling constants: Shifting and scaling factors for evaluating 1JCH

Computational NMR coupling constants: Shifting and scaling factors for evaluating 1JCH

Exploring Alternate Methods for the Calculation of High-Level Vibrational Corrections of NMR Spin–Spin Coupling Constants

Exploring Alternate Methods to High-Level Vibrational Correction Calculations of NMR Spin-Spin Coupling Constants

Contact Info

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Resources

About

Vibrational contributions to vicinal proton–proton coupling constants³J_HH

Computational NMR coupling constants: Shifting and scaling factors for evaluating ¹J_CH

Computational NMR coupling constants: Shifting and scaling factors for evaluating ¹J_CH