scholarly journals Basis set dependence of 1H–X spin–spin coupling constants in non-empirical pure DFT framework, X = 1H, 13C, 19F, 35Cl: Case of CHCl=CH–CF3 stereoisomers

AIP Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 035113
Author(s):  
Olivier Holtomo ◽  
Mama Nsangou ◽  
Ousmanou Motapon
Keyword(s):  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

scholarly journals Theoretical Investigation of Glycine Micro-Solvated. Energy and NMR Spin Spin Coupling Constants Calculations

Sci ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 41
Author(s):  
Maria Cristina Caputo ◽  
Patricio Federico Provasi
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Computational Study ◽  
Water Solution ◽  
Polarizable Continuum Model ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Glycine in its neutral form can exist in the gas phase while its zwitterion form is more stable in water solution, but how many waters are actually necessary to stabilize the zwitterionic structure in the gas phase? Are the intramolecular isotropic spin spin coupling constants sensitive enough to accuse the change in the environment? or the conformer observed? These and related questions have been investigated by a computational study at the level of density functional theory employing the B3LYP functional and the 6-31++G**-J basis set. We found that at least two water molecules explicitly accounted for in the super-molecule structure are necessary to stabilize both conformers of glycine within a water polarizable continuum model. At least half of the SSCCs of both conformers are very stable to changes in the environment and at least four of them differ significantly between Neutral and Zwitterion conformation.

Ab initio Study of Nitrogen-14 Nuclear Quadrupole Coupling and NMR Signal Linewidths in Some Azoles

1998 ◽  
Vol 53 (6-7) ◽  
pp. 362-369 ◽  
Author(s):  
Michał Jaszuński ◽  
Antonio Rizzo
Keyword(s):  
Ab Initio ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Quadrupole Coupling ◽  
Spin Coupling Constants ◽  
Nuclear Quadrupole ◽  
Spin Spin Coupling ◽  
Nmr Properties ◽  
Nmr Signals

Abstract Ab initio values of Nitrogen 14N Nuclear Quadrupole Coupling Constants (NQCC's) are calculated for a series of methyl-substituted azoles in the Multiconfigurational SCF (MCSCF) approximation. The four triazoles and two tetrazoles studied here are all isoelectronic. This enabled us to use the same level of approximation - basis set and active space -for all the molecules. The computed NQCC's are used to estimate the relative widths of the 14N NMR signals, assuming an identical effect of molecular tumbling for all the nuclei in a molecule and neglecting solvent effects. The linewidths for the unsubstituted N atoms are, in agreement with experiment, much larger than for the methyl-substituted N atom. For the 1-methyl-tetrazole we present also the NMR shielding and spin-spin coupling constants and discuss in some more detail the dependence of all calculated NMR properties on the basis set and correlation effects.

An efficient method for generating property-energy consistent basis sets. New pecJ-n (n = 1, 2) basis sets for high-quality calculations of indirect nuclear spin-spin coupling constants involving 1H, 13C, 15N, and 19F nuclei

2021 ◽  
Author(s):  
Yuriy Yu. Rusakov ◽  
Irina L Rusakova
Keyword(s):  
Efficient Method ◽  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Basis Sets ◽  
High Quality ◽  
Spin Coupling Constants ◽  
Consistent Basis ◽  
Spin Spin Coupling

This paper presents a new method of generating property-energy consistent (PEC) basis sets that can be applied to any arbitrary molecular property. The PEC method generates a basis set that...

Basis Set Convergence of Indirect Spin–Spin Coupling Constants in the Kohn–Sham Limit for Several Small Molecules

2012 ◽  
Vol 116 (14) ◽  
pp. 3728-3738 ◽  
Author(s):  
Teobald Kupka ◽  
Marzena Nieradka ◽  
Michał Stachów ◽  
Tadeusz Pluta ◽  
Piotr Nowak ◽  
...  
Keyword(s):  
Small Molecules ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Set Convergence ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Basis-set dependence of nuclear spin-spin coupling constants

1998 ◽  
Vol 99 (3) ◽  
pp. 175-182 ◽  
Author(s):  
Trygve Helgaker ◽  
Michał Jaszuński ◽  
Kenneth Ruud ◽  
Anna Górska
Keyword(s):  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

scholarly journals Theoretical Investigation of Glycine Micro-solvated. Energy and NMR Spin Spin Coupling Constants Calculations

2021 ◽  
Author(s):  
Maria Cristina Caputo ◽  
Patricio Federico Provasi
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Computational Study ◽  
Polarizable Continuum Model ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Polarizable Continuum

Glycine in its neutral form can exist in the gas phase while its zwitterion form is more stable in water solution.But how many waters are actually necessary to stabilize the zwitterionic structure in the gas phase? Are the intramolecular isotropic spin spin coupling constants sensitive enough to accuse the change in the environment? or the conformer observed? These and related questions have been investigated by a computational study at the level of density functional theory employing the B3LYP functional and the 6-31++G**-J basis set. We found that at least two water molecules explicitly accounted in the super-molecule structure are necessary to stabilize both conformers of glycine within a water polarizable continuum model. At least half of the SSCC’s of both conformers are very stable to changes in the environment and at least four of them differ significantly between Neutral and Zwitterion conformation.

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