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1.
2.
High resolution Fourier transform spectra in the 8–200 cm-1 spectral region have been used to analyse the pure rotation spectrum of nitrogen dioxide. In this way, the spin rotation levels of the (000) state were accurately measured for Ka up to 14 and N up to 54. Using a hamiltonian which takes the spin-rotation and the hyperfine operators explicitly into account, it has been possible to derive a complete set of molecular parameters (rotational, spin-rotation and hyperfine constants) for the (000) state of 14N16O2 from these experimental data and from the available microwave measurements. Numerous perturbations due to the hyperfine Fermi contact operator were analysed as well as a local resonance [42 0 42, J = 41·5] ? [41 2 40, J = 41·5] due to the electron spin-rotation interaction. Finally, a synthetic spectrum of the (000) ← (000) band of 14N16O2 including all hyperfine transitions has been computed, covering the 0–235 cm-1 spectral region. 相似文献
3.
C. W. P. Palmer 《Zeitschrift für Physik A Hadrons and Nuclei》1985,322(2):199-202
The two two-body operators representing the effect of far configurations on the contact hyperfine interaction in annl N n′s configuration are shown to reduce to one-body operators. In such a configuration the operator for the contact hyperfine field is (a nlSnl +an,ssn′s), where anl and an′s take the same values in all terms of the configuration. A discrepancy between expectation values of these two-body operators deduced from experiment and calculated values is explained. 相似文献
4.
Herbert M. Pickett 《Journal of Molecular Spectroscopy》2004,228(2):659-663
An automated procedure for determining symmetry-adapted spin eigenfunctions is developed for the Dn symmetry groups with n equivalent spins for arbitrary size of I and for n=3,…,6. These eigenfunctions are also eigenfunctions of the vector sum of the n equivalent nuclear spins. Generalized hyperfine spin operators are developed that have real matrix elements and that exploit the full symmetry. These spin operators can be combined with operators for other spins and molecular rotation using only real arithmetic. 相似文献
5.
Theoretical and experimental investigations of the hyperfine structure of deuterated acetaldehyde (CD3COH) are presented. The theoretical approach accounts for the large amplitude internal rotation of the CD3 group. A hyperfine Hamiltonian, depending on the large amplitude torsional angle, is written taking into account quadrupole hyperfine coupling arising from the three deuterium atoms. Effective hyperfine coupling Hamiltonians are derived for A- and E-type rotation-torsion levels. In the former case, a very symmetrical operator arises in which the hyperfine coupling is the same for all three deuterium atoms. In the latter case the operators are less symmetrical. Hyperfine levels are calculated using symmetry adapted hyperfine wavefunctions in order to build total hyperfine-rotation-torsion wavefunctions satisfying the Pauli exclusion principle. The theoretical approach is used to carry out analyses of six hyperfine patterns which were recorded using a pulsed molecular beam Fourier transform microwave spectrometer. The experimental resolution of this apparatus allows us to resolve individual hyperfine components in many cases. The results of the analysis are consistent with deuterium atoms having an effective quadrupole coupling tensor which, except for appropriate rotations, is quite close to that in CH3D. 相似文献
6.
Operators of representations corresponding to symmetric elements of theq-deformed algebrasU
q
(su1,1),U
q
(so2,1),U
q
(so3,1),U
q
(so
n
) and representable by Jacobi matrices are studied. Closures of unbounded symmetric operators of representations of the algebrasU
q
(su1,1) andU
q
(so2,1) are not selfadjoint operators. For representations of the discrete series their deficiency indices are (1,1). Bounded symmetric operators of these representations are trace class operators or have continuous simple spectra. Eigenvectors of some operators of representations are evaluated explicitly. Coefficients of transition to eigenvectors (overlap coefficients) are given in terms ofq-orthogonal polynomials. It is shown how results on eigenvectors and overlap coefficients can be used for obtaining new results in representation theory ofq-deformed algebras. 相似文献
7.
V. A. Ulanov M. M. Zaripov V. A. Shustov I. I. Fazlizhanov 《Physics of the Solid State》1998,40(3):408-414
Crystals of variable constituency CaxSr1−x
F2:Cu (0⩽x⩽0.05, x≅0.5, 1.0⩾x⩾0.95) are investigated by EPR and x-ray structural analysis. The electron-Zeeman, intrinsic hyperfine, and ligand hyperfine
interaction parameters are determined; they characterize the magnetic properties of the copper paramagnetic complexes formed
in the crystals. Models of the molecular structures of these complexes are discussed, along with the influence of structural
deformations and vibronic interactions on their magnetic properties.
Fiz. Tverd. Tela (St. Petersburg) 40, 445–451 (March 1998) 相似文献
8.
Biller JR Meyer V Elajaili H Rosen GM Kao JP Eaton SS Eaton GR 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,212(2):370-377
Optimization of nitroxides as probes for EPR imaging requires detailed understanding of spectral properties. Spin lattice relaxation times, spin packet line widths, nuclear hyperfine splitting, and overall lineshapes were characterized for six low molecular weight nitroxides in dilute deoxygenated aqueous solution at X-band. The nitroxides included 6-member, unsaturated 5-member, or saturated 5-member rings, most of which were isotopically labeled. The spectra are near the fast tumbling limit with T1∼T2 in the range of 0.50–1.1 μs at ambient temperature. Both spin–lattice relaxation T1 and spin–spin relaxation T2 are longer for 15N- than for 14N-nitroxides. The dominant contributions to T1 are modulation of nitrogen hyperfine anisotropy and spin rotation. Dependence of T1 on nitrogen nuclear spin state mI was observed for both 14N and 15N. Unresolved hydrogen/deuterium hyperfine couplings dominate overall line widths. Lineshapes were simulated by including all nuclear hyperfine couplings and spin packet line widths that agreed with values obtained by electron spin echo. Line widths and relaxation times are predicted to be about the same at 250 MHz as at X-band. 相似文献
9.
The hyperfine fields of Fe and Co in the substitutionally disorderedbcc alloy system Fe
x
Co1−x
due to the Fermi contact interaction have been studied by means of charge self-consistent cluster Korringa-Kohn-Rostoker-Coherent
Potential Approximation- (KKR-CPA) band structure calculations. The contribution to the Fermi contact hyperfine field due
to core polarisation was found to be proportional to the local moment for Fe as well as for Co throughout the concentration
range. On the other hand, the contributions of the conduction band did not show such a simple behavior, but were found to
be dominated by the population of the s-bands for spin up and down. These findings are completely analogous to those obtained
in a recent study of the ferromagnetic alloy systems Fe
x
Ni1−x
and Fe
x
Cr1−x
. To investigate the importance of relativistic effects on the Fermi contact hyperfine fields, the corresponding hyperfine
matrix elements have been calculated nonrelativistically as well as fully relativistically. The results of the present work
are compared with experiment as well as to theoretical data on related alloy systems. 相似文献
10.
By means of time-differential perturbed angular distribution (TDPAD) techniques, the magnetic hyperfine field ofF atoms implanted in a ferromagnetic Ni lattice has been measured at temperatures from 80 K to 650 K obtaining, for example, a fieldH
1(295 K)=+1.72(3)T at room temperature. The temperature dependence of the reduced fieldH
1(T)/H
1(0) has been found to deviate up to 38% from that of the reduced magnetization of the Ni host. Comparing this result for the halogenF with other nontransitional impurities in nickel, it seems that such deviations become more pronounced with increasing number of excessp-electrons of the impurity. With a simple two-zone model distinguishing between the hyperfine fields originating in the local and in the more distant undisturbed surrounding of theF impurity, the observed temperature dependence can be explained. In this approach the disturbed magnetization of the inner zone is described by localized Ni moments in the molecular field approximation.A satellite magnetic field of + 9.4T was observed at 80 K only.Supported by the Bundesministerium für Forschung und Technologie 相似文献
11.
H. C. Jain 《Hyperfine Interactions》1985,26(1-4):941-962
The decoupling experiments involving the time-differential perturbed angular correlation (TDPAC) of the 133–482 keV γ-γ cascade
in the presence of an external magnetic field applied along the quantization axis have been performed to measure the electric
quadrupole and the magnetic hyperfine interactions experienced by the181Ta nuclei at Hf sites in the pseudobinary compounds HfFe2-xSix, withx=0.1 andx=0.3. The hyperfine magnetic fields measured at 298 K areH
hf=133.1±12.0 kG in the cubic (C15) Laves phase compound HfFe1.9Si0.1 andH
hf=76.8±7.0 kG in the hexagonal (C14) Laves phase compound HfFe1.7Si0.3. The decoupling technique has also been used to obtain a —ve sign for the hyperfine field experienced by181Ta nuclei at the Ti or Hf sites in the Heusler compound Co2Ti0.8Hf0.2Sn and a+ve sign for the hyperfine field at Zr sites in the cubic (C15) Laves phase compound ZrFe2. 相似文献
12.
Finite nucleus models are used in the calculation of the dipole-dipole part of the second-order hyperfine energy in the ground state of the hydrogen atom. The results are used as a guide to bring the non-relativistic calculation for a point nucleus into agreement with the relativistic calculation. This necessitates the introduction of delta function operators in the dipole-dipole operator and the zeroth-order hamiltonian. It is concluded that the reduction of the Dirac equation to non-relativistic form is valid for the hyperfine interaction up to order mc 2α6. 相似文献
13.
W. Odermatt Hp. Baumeler H. Keller W. Kündig B. D. Patterson J. W. Schneider J. P. F. Sellschop M. C. Stemmet S. Connell D. P. Spencer 《Hyperfine Interactions》1986,32(1-4):583-588
Standard μSR experiments in diamond have shown that the relative sign of the hyperfine parameters of the anisotropic Mu* state is negative (A
‖/A
⊥<0). We report an experimental determination of theabsolute sign of the Mu* hyperfine parameters by studying the transferred muon polarization during the thermally-activated transition from the isotropic
Mu state to Mu*. The results demonstrate that the isotropic part of the Mu* hyperfine interaction is negative. In a nitrogen-poor diamond, both the Mu disappearance rate and the enhancement of the
Mu* signals are well-described by a single Arrhenius law. 相似文献
14.
The strong influence of relativity on the hyperfine interaction is demonstrated by non-, scalar andfully relativistic calculations for solid transition metal systems. By calculations of hyperfine fields andof the nuclear spin lattice relaxation rate of Ag in Ag
x
Pt1–x
it is shown that scalar relativistic calculations, which neglect the influence of spin-orbit coupling, seem to be sufficient to account for relativistic effects in many cases. To account properly for the symmetry-breaking caused by spin-orbit coupling, which is reflected by many hyperfine interaction properties, a fully relativistic approach is demanded. The corresponding formalism in the framework of the KKR-GF (Korringa-Kohn-Rostoker-Green's function) method of band structure calculation for magnetic solids is outlined. As applications results for the hyperfine fields of pure transition metals andalloys are presented. 相似文献
15.
Magnetization and57Fe Mössbauer measurements were carried out on RFe12–x
V
x
N
y
compounds (R=Y and Nd,x=1.7 and 2.2) and the effects of nitrogen and vanadium atoms on the57Fe hyperfine fields at the different iron crystallographic sites were investigated. The hyperfine field decreases with increasing number of vanadium neighbour atoms at all the iron sites. The hyperfine field is strongly enhanced in the nitrogen composition withy>1 where the compound tends to transform into an amorphous-like solid. The iron moment deduced from the hyperfine field increases more upon nitrogenation for the 8i-site than for the other sites, and exceeds the moment of bcc iron. 相似文献
16.
We consider two operators A and A
+ in a Hilbert space of functions on the exponential lattice , where 0<q<1. The operators are formal adjoints of each other and depend on a real parameter . We show how these operators lead to an essentially unique symmetric ground state ψ0 and that A and A
+ are ladder operators for the sequence . The sequence (ψ
n
/ψ0) is shown to be a family of orthogonal polynomials, which we identify as symmetrized q-Laguerre polynomials. We obtain in this way a new proof of the orthogonality for these polynomials. When γ=0 the polynomials
are the discrete q-Hermite polynomials of type II, studied in several papers on q-quantum mechanics.
Received: 6 December 1999 / Accepted: 21 May 2001 相似文献
17.
Jon-Paul R. Wells Glynn D. Jones Michael F. Reid Marina N. Popova Elena P. Chukalina 《Molecular physics》2013,111(11-12):1367-1376
Hyperfine structure is observed on several infrared transitions to the 5I7 and 5I6 multiplets of the Ho3+ C4v centre in CaF2. Particularly complex and detailed hyperfine structures are observed for transitions to the Y3 level of the 5I7 multiplet, which include the appearance of ΔIz ≠ 0 transitions. The hyperfine lines of this level are satisfactorily accounted for by strong mixing of close-lying levels of this multiplet by the perpendicular hyperfine interaction, which leads to relaxation of the ΔIz = 0 selection rule and a redistribution of the hyperfine intensities over many transitions. An excellent correspondence is found between the measured and simulated spectra. 相似文献
18.
Glasses with composition xBi2O3 ·(0.30 - x)BaO · 0.70B2O3 have been prepared in the range (0.00 ≤ x ≤ 0.15) containing 2.0 mol% of V2O5. Electron paramagnetic resonance (EPR), optical transmission and absorption spectra and DC conductivity of these glasses have been studied. The spin Hamiltonian parameters (SHP) of VO2+ ions, dipolar hyperfine coupling parameter P, Fermi contact interaction parameter K, and molecular orbital coefficients (α2 and γ2) have been calculated. The SHP arc related with the theoretical optical basicity. Ath. The position of the absorption edge and the values of the optical band gap have also been reported. The effect of addition of Bi2O3 on the DC conductivity has also been studied. 相似文献
19.
Ye. V. Baklanov M. V. Belyayev 《Applied Physics A: Materials Science & Processing》1977,14(4):389-391
The shift of components of the magnetic hyperfine structure (MHS) of a vibrational-rotational molecular transition in a weak
magnetic field is explored. The numerical data are given for the methane transition at λ=3.39 μm [theF
2
(2)
component of theP(7) line of thev
3 band]. The shift of the line contour due to the magnetic field is found when the MHS components overlap. 相似文献
20.
The amorphous fine particles of Fe100−x
B
x
(20.7≤x≤36.5) and (Fe70Co30)100−x
B
x
(26.9≤x≤40.2) were prepared by borohydride reduction. The amorphous state of the samples was identified with both X-ray and electron
diffraction measurements. With increasing boron content, the average hyperfine magnetic fields decrease. Comparing the hyperfine
parameters of the glassy powder with those of the ribbons having the same compositions, the average hyperfine fields and the
isomer shifts are different. The differences may be due to the amorphous polymorphism which is produced by the different preparation
methods.
Project is partly supported by the National Natural Science Foundation of China. 相似文献