Zeeman nuclear quadrupole resonance line shapes in powders (<i>I</i> = 3/2)

Brooker, H. R.; Creel, R. B.

doi:10.1063/1.1682549

Cited by 31 publications

(14 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For I = 3/2, there is a method devised (Morino & Toyama, 1961) which allows the evaluation of the two values from a powder Zeeman experiment. The shape of Zeeman NQR lines in crystal powder is considered by Brooker & Creel (1974). However, literature shows that only in a few cases are the correct data found.…”

Section: Methodsmentioning

confidence: 99%

The combination of X-ray diffraction and nuclear quadrupole resonance studies of crystals

Weiss¹

1995

Acta Crystallogr Sect B

View full text Add to dashboard Cite

The application of single-crystal Zeeman nuclear quadrupole resonance (NQR) in combination with diffraction studies is discussed. Bond directions and bond angles are found by the Zeeman spectroscopy of NQR, as are symmetry elements of the structures. Centrosymmetry may be differentiated from polar structures. Weak deformations of the valence electron shell by mutual polarization can be recognized and the double-bond character of a bond may be estimated. The method is quite valuable in the study of hydrogen bonds and of dynamics of molecules such as D20 and the groups --CD3 and ND3. Most useful is the method of the combination of X-and N-diffraction because of its sensitivity to the charge distribution around atoms and its location of time scale in dynamical effects.

show abstract

Section: Methodsmentioning

confidence: 99%

The combination of X-ray diffraction and nuclear quadrupole resonance studies of crystals

Weiss¹

1995

Acta Crystallogr Sect B

View full text Add to dashboard Cite

show abstract

“…Brooker and Creel [5] have shown that for / = 3/2 the features or peaks in the line-shape occur at the following critical points H//x, H//y and H//z, V0 » YH/atr . where .x, y, z refer to the 1, 2, 3 axes of the principal axes system.…”

Section: The Zeeman Line Shapes In Polycrystalline Materialsmentioning

confidence: 99%

“…Brooker and Creel [5] and Darville, Gerard and Calende [6] have independent ly given a full analysis of the problem where the applied magnetic field and the r.f. field were parallel.…”

Section: General Considerationsmentioning

confidence: 99%

Zeeman NQR Powder Line Shapes for Half Integral Spin Nuclei

Bryant

Hacobian

1986

Zeitschrift Für Naturforschung A

View full text Add to dashboard Cite

A polycrystalline material was simulated by assuming a random distribution o f small crystalites. The effect o f a small applied m agnetic field on the N Q R lineshape was calculated for half integral spin nuclei ( / = 3/2, 5/2, 7/2 and 9 /2 ) using a theory based on Toyam a's work [11], The line shapes indicate qualitatively the half width ratios o f the upper and lower resonances (e.g. A v1/Av] for 1=5/2) and thus enables one to see generally whether the broadening mechanism is mainly due to m agnetic or electric effects. General ConsiderationsConventionally, the Zeeman effect in NQR has been studied by the variations in the splittings of the resonance of a spin 3/2 system as the orientation of a single crystal was varied in the applied field [1,2,3], Morino and Toyama [4] were the first to show that a distinct effect was also observable in polycrystalline samples. Brooker and Creel [5] and Darville, Gerard and Calende [6] have independent ly given a full analysis of the problem where the applied magnetic field and the r.f. field were parallel. This has since been extended to other orientations and nuclei [7,8].In most polycrystalline samples studied by us so far with multilevel spin systems containing halogen nuclei (e.g. 127I), it has been shown that even for the best and most perfect crystalline samples, electrical broadening effects dominated [9,10]. As shown in a previous paper [10] with p-diiodobenzene, electrical broadening gives the ratio of 2.0 for the ratio of half widths of the upper and lower l27I lines. It can be qualitatively shown from the calculated line shapes in this paper that the half width NQR line ratio due to magnetic interaction is significantly less than 1.0 . In order to observe such magnetic broadening effects almost perfect crystals of p-diiodobenzene had to be obtained but since the compound has a tendency to decompose in heat and light it was not possible to obtain the desired conditions. Hence, it is proposed to present in the first instance the theoretical prediction of line shapes. To a large extent the theoretical treatment is based on solutions of equations developed by Toyama [11]. 2, The Zeeman Perturbation for H alf Integral SpinWhen a static magnetic field is applied to a nuclear quadrupolar system, the energy levels are determined by solving the secular eqation for the entire perturbed nuclear quadrupolar Hamiltonian ST, where z r = H Q + Hm. (l)Here Hq is the pure (unperturbed) nuclear quadru polar Hamiltonian and H m is that describing the magnetic interaction and is given by Hm = -y i H ,where y is the magnetogyric ratio and IH is the scalar product of the nuclear spin and applied magnetic field vectors. In the NQR case, the Zeeman effect is studied with external fields of the order of 100 gauss [1]. The nuclear magnetic dipoledipole fields are about 1 or 2 gauss and therefore the following perturbation treatment is a valid approximation.The eigenvalues of the nuclear quadrupolar Hamiltonian for half integral spins with finite asym metry parameter are given by m 'T...

show abstract

“…The Zeeman effect on NQR for powder specimens (PZNQR) has been studied theoretically and/or experimentally [1][2][3][4][5][6][7][8][9]. In the case of nuclear spin 3/2, an asymmetry parameter of electric field gradient (77) at the nuclear site cannot be determined only from the NQR frequency, so that the Zeeman NQR method using single crystal (SZNQR) has usually been adopted.…”

Section: Introductionmentioning

confidence: 99%

Powder Zeeman NQR Study on the Absorption Forms for Nuclear Spin 5/2

Ege

Nishijima

Kimura

et al. 1998

Zeitschrift Für Naturforschung A

View full text Add to dashboard Cite

For nuclei which have a nuclear spin of 5/2 and exhibit a small asymmetry parameter of the electric field gradient (77) at the nuclear site, line shapes of the Powder Zeeman NQR (PZNQR) spectra based on the transition between the energy levels m x = ± 1/2 and ± 3/2 (the lower frequency line) were studied by means of computer simulations and experiments, (i) When an 77 value is very small (type 1; 77 = 0), the line shape exhibits two shoulders like the style of the American football player, (ii) While an 77 value is small (type 2; 0< 77 < around 0.01) but not zero, the line shape has two small peaks which are symmetrically located on the shoulders, as in the case of the small 77 type of spin 3/2. (iii) When an 77 value is not small (type 3; around 0.01 <77), the line shape has two symmetrical dips in stead of the peaks, which are also similar to the case of not small 77 type of spin 3/2. As the 77 value increases from around 0.01, the two dips grow and reach the maximum at the 77 value of 0.349, and then become smaller and obscure in the range of 77 larger than 0.

show abstract

Zeeman nuclear quadrupole resonance line shapes in powders (I = 3/2)

Cited by 31 publications

References 18 publications

The combination of X-ray diffraction and nuclear quadrupole resonance studies of crystals

The combination of X-ray diffraction and nuclear quadrupole resonance studies of crystals

Zeeman NQR Powder Line Shapes for Half Integral Spin Nuclei

Powder Zeeman NQR Study on the Absorption Forms for Nuclear Spin 5/2

Contact Info

Product

Resources

About