# Dresden 2017 – wissenschaftliches Programm

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# MM: Fachverband Metall- und Materialphysik

## MM 35: Electronic Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond

### MM 35.11: Poster

### Dienstag, 21. März 2017, 18:30–20:30, P2-OG4

**A Hubbard ***U*** based correction method for exciton binding in neutral excitations: TDDFT+**** U** — •Okan K. Orhan and David D. O’Regan — School of Physics, Trinity College Dublin, Ireland.

The DFT+*U* (density-functional theory + Hubbard *U*) method is widely used to improve the approximate DFT description of the ground state properties of solids and molecules comprising transition-metal ions. We introduce its generalisation to the time domain in the guise of TDDFT+*U* (time-dependent DFT+*U*), intended to extend these improvements to the calculation of neutral excitations. Related methods have been previously discussed [1,2], and here we offer a detailed treatment emphasising single-particle excitations and absorption spectra. Our software implementation is a combination of the linear-scaling DFT+*U* [3] and linear-response TDDFT [4] functionalities available in the ONETEP code [5].
In a study of small nickel-comprising molecules, we find that the Hubbard *U* correction to the exchange-correlation kernel acts to partially cancel the effects of the DFT+*U* term of the underlying ground-state potential, enhancing the exciton binding.

[1] C.-C. Lee, H. C. Hsueh, and W. Ku, Phys. Rev. B **82**, 081106(R) (2010).
[2] D. Shin, G. Lee, Y. Miyamoto, and N. Park, J. Chem. Theory Comput., **12** (1), pp 201-208 (2016).
[3] D. D. O’Regan, N. D. M. Hine, M. C. Payne, and A. A. Mostofi, Phys. Rev. B **85**, 085107 (2012).
[4] T. J. Zuehlsdorff, N. D. M. Hine, M. C. Payne, and P. D. Haynes, J. Chem. Phys. **143**, 204107 (2015).
[5] C. K. Skylaris, P. D. Haynes, A. A. Mostofi, and M. C. Payne, J. Chem. Phys., **122** (8), 084119 (2005).
For the ONETEP code, see http://www.onetep.org