Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants
The Tamm-Dancoff approximation (TDA) can be applied to the computation of excitation energies using time-dependent Hartree-Fock (TD-HF) and time-dependent density-functional theory (TD-DFT). In addition to simplifying the resulting response equations, the TDA has been shown to significantly improve...
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Taylor & Francis
2015
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| Online Access: | https://eprints.nottingham.ac.uk/31093/ |
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| author | Cheng, Chi Y. Ryley, Matthew S. Peach, Michael J.G. Tozer, David J. Helgaker, Trygve Teale, Andrew M. |
| author_facet | Cheng, Chi Y. Ryley, Matthew S. Peach, Michael J.G. Tozer, David J. Helgaker, Trygve Teale, Andrew M. |
| author_sort | Cheng, Chi Y. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | The Tamm-Dancoff approximation (TDA) can be applied to the computation of excitation energies using time-dependent Hartree-Fock (TD-HF) and time-dependent density-functional theory (TD-DFT). In addition to simplifying the resulting response equations, the TDA has been shown to significantly improve the calculation of triplet excitation energies in these theories, largely overcoming issues associated with triplet instabilities of the underlying reference wave functions. Here, we examine the application of the TDA to the calculation of another response property involving triplet perturbations, namely the indirect nuclear spin-spin coupling constant. Particular attention is paid to the accuracy of the triplet spin-dipole and Fermi-contact components. The application of the TDA in HF calculations leads to vastly improved results. For DFT calculations, the TDA delivers improved stability with respect to geometrical variations but does not deliver higher accuracy close to equilibrium geometries. These observations are rationalized in terms of the ground- and excited-state potential energy surfaces and, in particular, the severity of the triplet instabilities associated with each method. A notable feature of the DFT results within the TDA is their similarity across a wide range of different functionals. The uniformity of the TDA results suggests that some conventional evaluations may exploit error cancellations between approximations in the functional forms and those arising from triplet instabilities. The importance of an accurate treatment of correlation for evaluating spin-spin coupling constants is highlighted by this comparison. |
| first_indexed | 2025-11-14T19:11:14Z |
| format | Article |
| id | nottingham-31093 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:11:14Z |
| publishDate | 2015 |
| publisher | Taylor & Francis |
| recordtype | eprints |
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| spelling | nottingham-310932020-05-04T20:10:42Z https://eprints.nottingham.ac.uk/31093/ Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants Cheng, Chi Y. Ryley, Matthew S. Peach, Michael J.G. Tozer, David J. Helgaker, Trygve Teale, Andrew M. The Tamm-Dancoff approximation (TDA) can be applied to the computation of excitation energies using time-dependent Hartree-Fock (TD-HF) and time-dependent density-functional theory (TD-DFT). In addition to simplifying the resulting response equations, the TDA has been shown to significantly improve the calculation of triplet excitation energies in these theories, largely overcoming issues associated with triplet instabilities of the underlying reference wave functions. Here, we examine the application of the TDA to the calculation of another response property involving triplet perturbations, namely the indirect nuclear spin-spin coupling constant. Particular attention is paid to the accuracy of the triplet spin-dipole and Fermi-contact components. The application of the TDA in HF calculations leads to vastly improved results. For DFT calculations, the TDA delivers improved stability with respect to geometrical variations but does not deliver higher accuracy close to equilibrium geometries. These observations are rationalized in terms of the ground- and excited-state potential energy surfaces and, in particular, the severity of the triplet instabilities associated with each method. A notable feature of the DFT results within the TDA is their similarity across a wide range of different functionals. The uniformity of the TDA results suggests that some conventional evaluations may exploit error cancellations between approximations in the functional forms and those arising from triplet instabilities. The importance of an accurate treatment of correlation for evaluating spin-spin coupling constants is highlighted by this comparison. Taylor & Francis 2015 Article PeerReviewed Cheng, Chi Y., Ryley, Matthew S., Peach, Michael J.G., Tozer, David J., Helgaker, Trygve and Teale, Andrew M. (2015) Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants. Molecular Physics, 113 (13-14). pp. 1937-1951. ISSN 1362-3028 nuclear magnetic resonance spin–spin coupling constants Hartree–Fock theory density–functional theory coupled-cluster theory http://dx.doi.org/10.1080/00268976.2015.1024182 doi:10.1080/00268976.2015.1024182 doi:10.1080/00268976.2015.1024182 |
| spellingShingle | nuclear magnetic resonance spin–spin coupling constants Hartree–Fock theory density–functional theory coupled-cluster theory Cheng, Chi Y. Ryley, Matthew S. Peach, Michael J.G. Tozer, David J. Helgaker, Trygve Teale, Andrew M. Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants |
| title | Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants |
| title_full | Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants |
| title_fullStr | Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants |
| title_full_unstemmed | Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants |
| title_short | Molecular properties in the Tamm–Dancoff approximation: indirect nuclear spin–spin coupling constants |
| title_sort | molecular properties in the tamm–dancoff approximation: indirect nuclear spin–spin coupling constants |
| topic | nuclear magnetic resonance spin–spin coupling constants Hartree–Fock theory density–functional theory coupled-cluster theory |
| url | https://eprints.nottingham.ac.uk/31093/ https://eprints.nottingham.ac.uk/31093/ https://eprints.nottingham.ac.uk/31093/ |