Theoretical study of 14N quadrupole coupling constants in some NO-containing complexes: N2O3 and FNO

Polák, R.; Fišer, Jiřı́

doi:10.1016/j.chemphys.2008.03.032

Cited by 7 publications

(4 citation statements)

References 46 publications

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“…The quadrupole coupling constants (χ αα ) are given as χ α α = e q α α Q where q αα is the electric field gradient along the α-axis at the nitrogen nucleus, e is the fundamental charge, and Q is the nuclear quadrupole moment. For the nitrogen quadrupole moment, we use the literature value of 20.44 mb . As seen for ammonia (Table S6, Supporting Information), the accurate computation of electric field gradients at the nuclei presents a difficult theoretical problem.…”

Section: Resultsmentioning

confidence: 99%

“…For the nitrogen quadrupole moment, we use the literature value of 20.44 mb. 89 As seen for ammonia (Table S6, Supporting Information), the accurate computation of electric field gradients at the nuclei presents a difficult theoretical problem. Similar difficulties hold for spin-dependent properties that depend on contact terms since the amplitude and shape of the wave function near the nuclei must be very accurately described.…”

Section: Structural Effects On Relative Energiesmentioning

confidence: 99%

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Conformers of Gaseous Cysteine

Wilke

Lind

Schaefer

et al. 2009

J. Chem. Theory Comput.

126

168

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Structures, accurate relative energies, equilibrium and vibrationally averaged rotational constants, quartic and sextic centrifugal distortion constants, dipole moments, (14)N nuclear quadrupole coupling constants, anharmonic vibrational frequencies, and double-harmonic infrared intensities have been determined from ab initio electronic structure computations for conformers of the neutral form of the natural amino acid l-cysteine (Cys). A systematic scan located 71 unique conformers of Cys using the MP2(FC)/cc-pVTZ method. The large number of structurally diverse low-energy conformers of Cys necessitates the highest possible levels of electronic structure theory to determine their relative energies with some certainty. For this reason, we determined the relative energies of the lowest-energy eleven conformers, accurate within a standard error (1σ) of about 0.3 kJ mol(-1), through first-principles composite focal-point analyses (FPA), which employed extrapolations using basis sets as large as aug-cc-pV(5+d)Z and correlation treatments as extensive as CCSD(T). Three and eleven conformers of l-cysteine fall within a relative energy of 6 and 10 kJ mol(-1), respectively. The vibrationally averaged rotational constants computed in this study agree well with Fourier-transform microwave spectroscopy results. The effects determining the relative energies of the low-energy conformers of cysteine are analyzed in detail on the basis of hydrogen bond additivity schemes and natural bond orbital analysis.

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Section: Resultsmentioning

confidence: 99%

Section: Structural Effects On Relative Energiesmentioning

confidence: 99%

Conformers of Gaseous Cysteine

Wilke

Lind

Schaefer

et al. 2009

J. Chem. Theory Comput.

126

168

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show abstract

“…How-ever, the classification is robust and all methods studied by us including Hartree-Fock (HF) and DFT show the same qualitative classification (except for FNO). The geometry, energy and properties of FNO are all extremely sensitive to correlation and need at least CCSD(T) level computations for reasonable accuracy 75 . The values of the susceptibilities cannot be determined with any reasonable accuracy with our set of methods.…”

Section: B Classificationmentioning

confidence: 99%

Benchmarking density functional approximations for diamagnetic and paramagnetic molecules in nonuniform magnetic fields

Sen

Tellgren

2020

Preprint

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“…However, the classification is robust and all methods studied by us including Hartree–Fock (HF) and DFT show the same qualitative classification (except for FNO). The geometry, energy, and properties of FNO are all extremely sensitive to correlation and need at least CCSD(T) level computations for reasonable accuracy . The values of the susceptibilities cannot be determined with any reasonable accuracy with our set of methods.…”

Section: Resultsmentioning

confidence: 99%

Benchmarking Density Functional Approximations for Diamagnetic and Paramagnetic Molecules in Nonuniform Magnetic Fields

Sen¹,

Tellgren

2021

J. Chem. Theory Comput.

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In this article, correlated studies on a test set of 36 small molecules are carried out with both wavefunction (HF, MP2, CCSD) and density functional (LDA, KT3, cTPSS, cM06-L) methods. The effect of correlation on exotic response properties such as molecular electronic anapole susceptibilities is studied and the performance of the various density functional approximations are benchmarked against CCSD and/or MP2. Atoms and molecules are traditionally classified into "diamagnetic" and "paramagnetic" based on their isotropic response to uniform magnetic fields. However, in this article, we propose a more fine-grained classification of molecular systems on the basis of their response to generally nonuniform magnetic fields. The relation of orientation to different qualitative responses is also considered.

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Theoretical study of 14N quadrupole coupling constants in some NO-containing complexes: N2O3 and FNO

Cited by 7 publications

References 46 publications

Conformers of Gaseous Cysteine

Conformers of Gaseous Cysteine

Benchmarking density functional approximations for diamagnetic and paramagnetic molecules in nonuniform magnetic fields

Benchmarking Density Functional Approximations for Diamagnetic and Paramagnetic Molecules in Nonuniform Magnetic Fields

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