Magnetic-field-dependent molecular susceptibility

Žaucer, Matjaž; Ažman, A.

doi:10.1103/physreva.16.475

Cited by 22 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A systematic study of molecular response to intense magnetic fields in the lower limit of the socalled intermediate regime, in which matter interacts with fields from 10 3 to 10 5 T [9], was undertaken in a series of previous articles [10][11][12][13][14], showing that cubic response produces changes of magnetizability and magnetic shielding at the nuclei, which are interpreted in terms of fourth-rank tensors, e.g., hypermagnetizabilities [15] and nuclear magnetic hypershieldings [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Geometry distortion of the benzene molecule in a strong magnetic field

Caputo

Lazzeretti

2010

Int J of Quantum Chemistry

View full text Add to dashboard Cite

ABSTRACT:The electrostatic Lorentz force acting on the H and C nuclei of a benzene molecule in the presence of a strong magnetic field with flux density B has been estimated via Rayleigh-Schrödinger perturbation theory to second order in B. In stationary conditions, a new equilibrium configuration is reached, at which the total force has been entirely transferred to the nuclei, and the force on the electrons vanishes. The distortion of the molecular geometry is rationalized in terms of third-rank electric hypershielding at the nuclei, induced by strong magnetic fields applied along three Cartesian axes. The nuclear hypershielding has been evaluated at near Hartree-Fock level of accuracy by its definition within the Rayleigh-Schrödinger perturbation theory, and by a pointwise procedure for the geometrical derivatives of magnetic susceptibilities. The connection between these two quantities is provided by the Hellmann-Feynman theorem. A field along the C 6 symmetry axis causes a symmetric contraction of the carbon ring and an elongation of the CH bonds. A field along one of the C 2 symmetry axes containing two CH bond acts to shorten them, to widen the ring, and to bend the four remaining CH bonds towards C 2 . A field along one of the C 2 symmetry axes through the midpoint of two opposite CC bonds causes a spindle effect, by squeezing the molecule toward the center of mass. Constraints for rotational and translational invariance and hypervirial theorems provide a natural criterion for Hartree-Fock quality of computed nuclear electric hypershielding. However, the molecular distortion is negligible for applied fields usually available in a laboratory.

show abstract

Section: Introductionmentioning

confidence: 99%

Geometry distortion of the benzene molecule in a strong magnetic field

Caputo

Lazzeretti

2010

Int J of Quantum Chemistry

View full text Add to dashboard Cite

show abstract

“…9 Experimental evidence in the lower limit of the intermediate regime, where conventional methods of perturbation theory are applicable, has been sought by some authors. [10][11][12][13][14][15][16][17][18][19] Vaara and co-workers reported theoretical investigations of nuclear magnetic shielding in closed-shell atomic systems as a function of even powers of a strong perturbing magnetic field 11 and analyzed the magnetic-field dependence of 59 Co nuclear magnetic shielding in Co(III) complexes. 12 A computational scheme based on Rayleigh-Schro ¨dinger perturbation theory has been developed to evaluate 10 propagators appearing in the quantum mechanical definition of the fourth-rank hypershielding 〈Σ Rβγδ I 〉 of the Ith nucleus in a molecule.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Hypershielding Contribution to Isotropic Nitrogen Shielding in Strong Magnetic Fields

Boyd¹,

Pagola

Caputo

et al. 2009

J. Chem. Theory Comput.

View full text Add to dashboard Cite

Hypershielding contributions to magnetic shielding of the nitrogen N nucleus have been evaluated for some nitroso (RNO) and isodiazene (R 1 R 2 NN) compounds in the presence of an external spatially uniform, time-independent magnetic field, accounting for cubic response via Rayleigh-Schro ¨dinger perturbation theory. Numerical estimates have been obtained at the coupled Hartree-Fock level of accuracy within the conventional common-origin approach. Medium-size basis sets of gaugeless (that is, without gauge-including phase factors) Gaussian functions have been employed in a numerical test to show that the isotropic hypershielding contribution τ N B 2 , τ N ) 1/2〈Σ Rβγδ N 〉, eqs 2-4 in the text, to average nitrogen shielding in PhNO (τ N ≈ 1.1 × 10 -5 ppm T -2 ), (CH 3 ) 3 CNO (τ N ≈ 2.3 × 10 -5 ppm T -2 ), and (CH 3 ) 2 NN (τ N ≈ 4.4 × 10 -5 ppm T -2 ) are similar and quite large. For 15 N at the highest currently available high-resolution NMR field strength of 22.3 T (ω H /2π ) 950 MHz, ω 15 N /2π ) 96.3 MHz) the change due to the additional shielding contribution for these compounds is between ∼0.5 and ∼2 Hz to lower frequency (upfield). Employing modern NMR instrumentation, shielding perturbations of this magnitude are, in principle, within detection limits, although instrumental instabilities and other field-dependent shielding phenomena make unambiguous detection at different field strengths difficult.

show abstract

“…Bendall and Doddrell reported an experimental observation of a fielddependent 59 Co chemical shift in two compounds. 31 Z ´aucer and Az ´man 33 suggested that departures from linear dependence between the induced magnetic dipole moment and the applied field can arise in a molecule, due to magnetic field dependence of the magnetic susceptibility. Magnetic fielddependent nuclear spin-spin coupling was discussed by Raynes and Stevens via fourth-order perturbation theory.…”

Section: Perturbation Theory Approach To Cubic Responsementioning

confidence: 99%

Can Induced Orbital Paramagnetism Be Controlled by Strong Magnetic Fields?

Pagola¹,

Ferraro²,

Lazzeretti³

2009

J. Chem. Theory Comput.

View full text Add to dashboard Cite

Magnetic hypersusceptibilities and hypershielding at the nuclei of BH, CH(+), C4H4, and C8H8 molecules in the presence of an external spatially uniform, time-independent magnetic field have been investigated accounting for cubic response contributions via Rayleigh-Schrödinger perturbation theory. Numerical estimates have been obtained at the coupled Hartree-Fock and density-functional levels of theory within the conventional common-origin approach, using extended gaugeless basis sets. The fundamental role of electron correlation effects was assessed. Critical values of the applied magnetic field at which transition from paramagnetic to diamagnetic behavior would occur were estimated. It is shown that perturbative methods may successfully be employed to estimate the interaction energy for big cyclic molecules.

show abstract

Magnetic-field-dependent molecular susceptibility

Cited by 22 publications

References 5 publications

Geometry distortion of the benzene molecule in a strong magnetic field

Geometry distortion of the benzene molecule in a strong magnetic field

Calculation of Hypershielding Contribution to Isotropic Nitrogen Shielding in Strong Magnetic Fields

Can Induced Orbital Paramagnetism Be Controlled by Strong Magnetic Fields?

Contact Info

Product

Resources

About