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Parametrization and Benchmark of Long-Range Corrected DFTB2 for Organic Molecules

Abstract : We present the parametrization and benchmark of long-range corrected second-order density functional tight binding (DFTB), LC-DFTB2, for organic and biological molecules. The LC-DFTB2 model not only improves fundamental orbital energy gaps but also ameliorates the DFT self-interaction error and overpolarization problem, and further improves charge-transfer excited states significantly. Electronic parameters for the construction of the DFTB2 Hamiltonian as well as repulsive potentials were optimized for molecules containing C, H, N, and O chemical elements. We use a semiautomatic parametrization scheme based on a genetic algorithm. With the new parameters, LC-DFTB2 describes geometries and vibrational frequencies of organic molecules similarly well as third-order DFTB3/3OB, the de facto standard parametrization based on a GGA functional. LC-DFTB2 performs well also for atomization and reaction energies, however, slightly less satisfactorily than DFTB3/3OB.
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Contributor : Marie-Gabrielle Chautard <>
Submitted on : Tuesday, September 17, 2019 - 10:59:05 AM
Last modification on : Thursday, October 15, 2020 - 8:54:03 AM

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V. Q. Vuong, J. A. Kuriappan, M. Kubillus, J. J. Kranz, T. Mast, et al.. Parametrization and Benchmark of Long-Range Corrected DFTB2 for Organic Molecules. Journal of Chemical Theory and Computation, American Chemical Society, 2018, 14 (1), pp.115-125. ⟨10.1021/acs.jctc.7b00947⟩. ⟨hal-02289867⟩



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