Applications and validations of the Minnesota density functionals

Zhao, Yan; Truhlar, Donald G.

doi:10.1016/j.cplett.2010.11.060

“…Taking the MP2/6-311++G(d,p)//B3LYP/6-311++G(d,p) results as the comparative datum, we find reasonable agreement between the M062X/6-311++G(d,p) and MP2/6-311++G(d,p)//B3LYP/6-311++G(d,p) findings in terms of both the quantitative relative energies and qualitative rank orders (Tables 1 and 2; Figure 3), similar to our prior work on the 89 PFOS congeners [6] and consistent with the known excellent performance of the M062X functional for estimating isomerization energies [26][27][28][29][30]. The wB97XD functional with long range and empirical dispersion corrections performs approximately midway between the M062X and B3LYP functionals.…”

Section: The Gas and Solution Phase Relative Thermodynamic Stabilitiesupporting

confidence: 75%

Comparative theoretical investigation on the isomerization energies of long-chain perfluoroalkanes: A case study with perfluorooctanoic acid congeners

Rayne¹,

Forest²

2011

Nature Precedings

0

View full text Add to dashboard Cite

The gas and solution phase relative thermodynamic stabilities of the 39 linear and branched perfluorooctanoic acid (PFOA) congeners in both their acid and anionic forms were calculated at various levels of density functional (B3LYP, wB97XD,p) basis set) and second order p) Perfluorinated carboxylic acids (PFCAs; Figure 1) are ubiquitous environmental contaminants that arise from direct production and use, as well as via the degradation of various perfluoroalkyl precursor materials [1]. Analogous to their perfluorooctane sulfonic acid (PFOS) analogs, the gas and solution phase relative thermodynamic stabilities of the 39 PFOA congeners [2] play an important role in assessing whether synthetic conditions for commercial mixtures are under thermodynamic or kinetic control and to allow calculation of various physicochemical properties [3][4][5]. In previous work [3, 5, 6], we reported on comparative semiempirical, density functional (DFT), and second order Moller-Plesset perturbation [MP2] theory studies into the relative thermodynamic stabilities of the 89 PFOS congeners in their neutral and anionic forms. These prior investigations collectively demonstrated that the B3LYP functional does not accurately model the relative thermodynamic stabilities of linear versus branched perfluoroalkyl chains, and that more modern functionals such as M062X [7] or higher-level calculations are required to estimate the expected thermodynamic behavior of these compounds. In the current study, we extend these efforts towards calculating the gas and solution phase relative thermodynamic stabilities of the 39 linear and branched PFOA congeners. For all isomers, MMFF94 [8-11] molecular mechanics force field method systematic rotor searches (Avogadro 1.0.1) were conducted to identify the respective lowest energy conformers that were subsequently subjected to higher level DFT and MP2 calculations. Calculations were performed using the B3LYP [12][13][14]

show abstract

“…Significant differences were found between the B3LYP/6-311++G(d,p), wB97XD/6-311++G(d,p), M062X/6-311++G(d,p), and MP2/6-311++G(d,p)//B3LYP/6-311++G(d,p) predictions for the gas phase relative thermodynamic stabilities of the acid form PFOA congeners (Figure 2 Figure 3), similar to our prior work on the 89 PFOS congeners [6] and consistent with the known excellent performance of the M062X functional for estimating isomerization energies [26][27][28][29][30]. The wB97XD functional with long range and empirical dispersion corrections performs approximately midway between the M062X and B3LYP functionals.…”

Section: The Gas and Solution Phase Relative Thermodynamic Stabilitiesupporting

confidence: 71%

Comparative theoretical investigation on the isomerization energies of long-chain perfluoroalkanes: A case study with perfluorooctanoic acid congeners

Rayne

¹

,

Forest

²

2011

Nat Prec

0

View full text Add to dashboard Cite

The gas and solution phase relative thermodynamic stabilities of the 39 linear and branched perfluorooctanoic acid (PFOA) congeners in both their acid and anionic forms were calculated at various levels of density functional (B3LYP, wB97XD,p) basis set) and second order p) Perfluorinated carboxylic acids (PFCAs; Figure 1) are ubiquitous environmental contaminants that arise from direct production and use, as well as via the degradation of various perfluoroalkyl precursor materials [1]. Analogous to their perfluorooctane sulfonic acid (PFOS) analogs, the gas and solution phase relative thermodynamic stabilities of the 39 PFOA congeners [2] play an important role in assessing whether synthetic conditions for commercial mixtures are under thermodynamic or kinetic control and to allow calculation of various physicochemical properties [3][4][5]. In previous work [3, 5, 6], we reported on comparative semiempirical, density functional (DFT), and second order Moller-Plesset perturbation [MP2] theory studies into the relative thermodynamic stabilities of the 89 PFOS congeners in their neutral and anionic forms. These prior investigations collectively demonstrated that the B3LYP functional does not accurately model the relative thermodynamic stabilities of linear versus branched perfluoroalkyl chains, and that more modern functionals such as M062X [7] or higher-level calculations are required to estimate the expected thermodynamic behavior of these compounds. In the current study, we extend these efforts towards calculating the gas and solution phase relative thermodynamic stabilities of the 39 linear and branched PFOA congeners. For all isomers, MMFF94 [8-11] molecular mechanics force field method systematic rotor searches (Avogadro 1.0.1) were conducted to identify the respective lowest energy conformers that were subsequently subjected to higher level DFT and MP2 calculations. Calculations were performed using the B3LYP [12][13][14]

show abstract

“…Calculations were carried out using the hybrid meta GGA exchange-correlation functional M05-2X with a double fraction of Hartree-Fock exchange developed by Zhao and Truhlar [53]. According to literature data this functional performs very well in DFT studies of the adsorption of hydrocarbons on a large 16T zeolite model cluster [54,55] or modeling of water-zeolite interaction [56].…”

Section: Computationsmentioning

confidence: 99%

Monomer- and polymer radicals of vinyl compounds: EPR and DFT studies of geometric and electronic structures in the adsorbed state

Lund

¹

,

Danilczuk

²

2012

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

3

1

0

View full text Add to dashboard Cite

Electron paramagnetic resonance (EPR) spectroscopy was applied to study the paramagnetic species formed from styrene, 1,1-diphenylethylene, α-methylstyrene, β-methylstyrene and methylmethacrylate adsorbed on amorphous silica gel after -irradiation at 77 K. Radicals formed by the hydrogen atom addition at the vinyl group of the monomers were observed in all samples. The hydrogen atoms were shown to originate to a large extent from the adsorbent by using silica gel with deuterated silanol groups. An EPR spectrum assigned to a propagating radical was observed at increased temperature for samples containing methylmethacrylate (MMA). The structures of the adsorption complexes, the respective hyperfine coupling constants and the adsorption energies were calculated by applying DFT quantum chemical methods. The reaction between an MMA molecule and the MMA radical and the structure of the propagating radical was modeled. The calculated hyperfine coupling constants for all radicals confirmed the assignment of the experimental spectra.3

show abstract

Applications and validations of the Minnesota density functionals

Cited by 686 publications

References 251 publications

Comparative theoretical investigation on the isomerization energies of long-chain perfluoroalkanes: A case study with perfluorooctanoic acid congeners

Comparative theoretical investigation on the isomerization energies of long-chain perfluoroalkanes: A case study with perfluorooctanoic acid congeners

Comparative theoretical investigation on the isomerization energies of long-chain perfluoroalkanes: A case study with perfluorooctanoic acid congeners

Monomer- and polymer radicals of vinyl compounds: EPR and DFT studies of geometric and electronic structures in the adsorbed state

Contact Info

Product

Resources

About