Permanent dipole moments and energies of excited states from density functional theory compared with coupled cluster predictions: Case of para-nitroaniline

    Authors

    I. A. Mikhailov; M. Musial;A. E. Masunov

    Comments

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    Abbreviated Journal Title

    Comput. Theor. Chem.

    Keywords

    Para-nitroaniline; Density Functional Theory; Dipole moment; Excited; states; Excitation energies; Delta-SCF; NONLINEAR-OPTICAL MATERIALS; EXCITATION-ENERGIES; 2-PHOTON ABSORPTION; RESPONSE FUNCTIONS; S-1 STATE; GAS-PHASE; TD-DFT; MOLECULES; SPECTROSCOPY; HYPERPOLARIZABILITY; Chemistry, Physical

    Abstract

    Different ways to extract properties of excited states from time-dependent density functional theory (TD-DFT) calculations are compared to ab initio results obtained with the Equation of Motion Coupled Cluster approach. The recently proposed a posteriori Tamm-Dancoff approximation (ATDA) predicts the permanent dipole moments to be underestimated by 25% on average, close to the results of the relaxed density TD-DFT formalism, quadratic response formalism, and numerical energy derivatives, while the unrelaxed density approximation results are less accurate (40% overestimate). We also propose a correction for TD-DFT excitation energies, which are known to be problematic for charge transfer states. The static DFT energies evaluated on the relaxed densities of the excited states are found to be more accurate than TD-DFT excitation energies (RMSD is 0.7 eV vs. 1.1 eV, while maximum deviation is -1.0 eV vs. -2.0 eV). This validates ATDA for description of nonlinear optical properties of donor-acceptor molecules, exemplified by para-nitroaniline, and extends this method to improve the excitation energy predictions. (C) 2013 Elsevier B.V. All rights reserved.

    Journal Title

    Computational and Theoretical Chemistry

    Volume

    1019

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    23

    Last Page

    32

    WOS Identifier

    WOS:000324008100004

    ISSN

    2210-271X

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