Development and Validation of the B3LYP/N07D Computational Model for Structural Parameter and Magnetic Tensors of Large Free Radicals

Barone, Vincenzo; Cimino, Paola; Stendardo, Emiliano

doi:10.1021/ct800034c

Cited by 244 publications

(229 citation statements)

References 61 publications

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“…The B3LYP/N07D method has been employed to calculate anharmonic frequencies of several closed-and open-shell molecular systems 43,90,117,[125][126][127][128][129][130][131] , and a recent extension of N07D, the SNSD basis set, with the inclusion of diffuse s functions on all atoms and one set of diffuse polarized functions, d on heavy and p on hydrogen atoms, has improved its performance (Double and triple-ζ basis sets of SNS and N07 families, are available for download. 2012; visit http:// dreamslab.sns.it) 132,133 .…”

Section: Computational Detailsmentioning

confidence: 99%

Dispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers

Fornaro

Biczysko

Monti

et al. 2014

Phys. Chem. Chem. Phys.

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101

113

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Computational spectroscopy techniques have become in the last years effective means to analyze and assign infrared (IR) spectra for molecular systems of increasing dimensions and in different environments. However, transition from compilations of harmonic data to full anharmonic simulations of spectra is still under way. The most promising results for large systems have been obtained, in our opinion, by perturbative vibrational approaches based on potential energy surfaces computed by hybrid (especially B3LYP) density functionals and medium size (e.g. SNSD) basis sets. In this framework, we are actively developing a comprehensive and robust computational protocol aimed to a quantitative reproduction of the spectra of nucleic acid bases complexes and their adsorption on solid supports (organic/inorganic). In this contribution we report the essential results of the first step devoted to isolated monomers and dimers. It is well known that in order to model the vibrational spectra of weakly bound molecular complexes dispersion interactions should be taken into proper account. In this work, we have chosen two popular and inexpensive approaches to model dispersion interaction, namely the semi-empirical dispersion correction (D3) and pseudopotential based (DCP) methodologies both in conjunction with the B3LYP functional. These have been used for simulating fully anharmonic IR spectra of nucleobases and their dimers through generalized second order vibrational perturbation theory (GVPT2). We have studied, in particular, isolated adenine, hypoxanthine, uracil, thymine and cytosine, the hydrogen-bonded and stacked adenine and uracil dimers, and the stacked adenine-naphthalene heterodimer. Anharmonic frequencies are compared with standard B3LYP results and experimental findings, while the computed interaction energies and structures of complexes are compared to the best available theoretical estimates.

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Section: Computational Detailsmentioning

confidence: 99%

Dispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers

Fornaro

Biczysko

Monti

et al. 2014

Phys. Chem. Chem. Phys.

Self Cite

101

113

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“…[7][8][9][10][11][12][13][14][15][16][17][18] The lack of such analysis tools forced early investigations of EPR data to rely on rules-of-thumb or simple principles that relate the spin density to the measured hyperfine coupling constants (HFCCs). One such relation is the McConnell relation that states that the spin density ρ C on the carbon of a C-H fragment in an organic π radical is linearly dependent on the isotropic hyperfine constant of hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Role of zero-point vibrational corrections to carbon hyperfine coupling constants in organic π radicals

Xiao

Rinkevičius

Ruud

et al. 2013

The Journal of Chemical Physics

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By analyzing a set of organic π radicals, we demonstrate that zero-point vibrational corrections give significant contributions to carbon hyperfine coupling constants, in one case even inducing a sign reversal for the coupling constant. We discuss the implications of these findings for the computational analysis of electron paramagnetic spectra based on hyperfine coupling constants evaluated at the equilibrium geometry of radicals. In particular, we note that a dynamical description that involves the nuclear motion is in many cases necessary in order to achieve a semi-quantitatively predictive theory for carbon hyperfine coupling constants. In addition, we discuss the implications of the strong dependence of the carbon hyperfine coupling constants on the zero-point vibrational corrections for the selection of exchange-correlation functionals in density functional theory studies of these constants.

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“…Except when written otherwise, the B3LYP functional 52 with the double-ζ basis set SNSD 53 , developed for spectroscopic studies of medium-to-large molecular systems, has been used. This basis set has been built from the polarized double-ζ basis set N07D [54][55][56][57] by consistently including diffuse s functions on all atoms, and one set of diffuse polarized functions (d on heavy atoms and p on hydrogens). For benzyl radical, basis set cc-pVTZ was used together with B3LYP, while for Tris(bipyridine)ruthenium(II) chloride, the B3PW91 functional 58 together with basis set LanL2DZ 59 has been used.…”

Section: Computational Detailsmentioning

confidence: 99%

A general time-dependent route to Resonance-Raman spectroscopy including Franck-Condon, Herzberg-Teller and Duschinsky effects

Baiardi

Bloino

Barone

2014

The Journal of Chemical Physics

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We present a new formulation of the time-dependent theory of Resonance-Raman spectroscopy (TD-RR). Particular attention has been devoted to the generality of the framework and to the possibility of including different effects (Duschinsky mixing, Herzberg-Teller contributions). Furthermore, the effects of different harmonic models for the intermediate electronic state are also investigated. Thanks to the implementation of the TD-RR procedure within a general-purpose quantum-chemistry program, both solvation and leading anharmonicity effects have been included in an effective way. The reliability and stability of our TD-RR implementation are first validated against our previously proposed and well-tested time-independent procedure. Practical applications are illustrated with some closed-and open-shell medium-size molecules (anthracene, phenoxyl radical, benzyl radical) and the simulated spectra are compared to the experimental results. More complex and larger systems, not limited to organic compounds, are also feasible, as shown for the case of Tris(bipyridine)ruthenium(II) chloride.

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Development and Validation of the B3LYP/N07D Computational Model for Structural Parameter and Magnetic Tensors of Large Free Radicals

Cited by 244 publications

References 61 publications

Dispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers

Dispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers

Role of zero-point vibrational corrections to carbon hyperfine coupling constants in organic π radicals

A general time-dependent route to Resonance-Raman spectroscopy including Franck-Condon, Herzberg-Teller and Duschinsky effects

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