• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 90
  • 13
  • 7
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 2
  • 2
  • 1
  • Tagged with
  • 137
  • 137
  • 33
  • 27
  • 26
  • 23
  • 15
  • 15
  • 12
  • 11
  • 11
  • 9
  • 9
  • 9
  • 9
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Self-consistent-field nuclear wave functions for O¹⁶, O¹⁵ and explanation of spin-orbit coupling through tensor force

Ullah, Nazakat January 1962 (has links)
Thesis (Ph.D.)--Boston University / A matrix version of Hartree-Fock self-consistent-field calculation is applied to O^16 and O^15 nuclei. The two-body interaction operator employed has a Serber exchange character with repulsive core and tensor component. A projection operator technique has been used to construct 1/S wave functions from the various excited configurations which interact with the ground state. The configuration interaction calculation gives the ground state energy of O^16 to be -129.91 mev, neglecting the coulomb forces, which contribute 18.24 mev. An attempt is made to perturb the shell model ground state wave function by mixing d orbital with occupied p orbital and f orbital with occupied s orbital, but it turned out that no such mixing occurs. The p(3/2) - p(1/2) splitting in O^15 nucleus due to the tensor force is estimated to be 4.05 mev, but the calculation puts the P(3/2) level lower than the p(1/2) level

Spin density calculations

Tortorelli, James J. January 1978 (has links)
Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 218-224).

On the spin wave approximation in the theory of magnetically ordered crystals

Pink, David Anthony January 1964 (has links)
The question of the self-consistency of spin wave theory as applied to different spin arrangements in magnetically ordered crystals has been reinvestigated. A set of equations, involving the probabilities of finding a given number of spin deviations at a given site first proposed by Van Kranendonk and Van Vleck (1958) in connection with a simple cubic antiferromagnet at a temperature of 0°K, is generalised and solved exactly for an arbitrary temperature. Two sets of equations are solved both for the case of a simple cubic antiferromagnet and for more general spin arrangements, collectively referred to as spiral spin arrangements. In solving for the probabilities a method is developed for easy calculation of the thermal average of certain functions of number operators. Finally, numerical results are given for some probabilities connected with: (i) the simple cubic antiferromagnet and (ii) a model of the rare earth metal, dysprosium. The latter is of some interest in view of the investigations of spiral spin arrangements in recent years. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Novelties Associated with a biodynamical interpretation of nuclear spin relaxation

Werbelow, Lawrence Glen January 1974 (has links)
Employing the semiclassical form of the density operator theory of dynamic processes, the transient nuclear spin behavior is analyzed for a range of motional parameters of significance for biological interpretations of nuclear magnetic relaxation data. Only relaxation which results solely from the reorientational modulation of the various spin couplings is considered. The bath correlation functions which enter into the theory are assumed to be completely characterized by two unique motional constants (a dynamic symmetric top approximation). The effects of slow, anisotropic modulation of spin-spin and spin-molecule interactions on T₁, T₂, T₁ ratios, T₂ ratios, and Overhauser enhancements are discussed. It is rationalized that in general, any parameter dependent upon the spectral density at zero frequency is independent of the magnitude of the asymmetry in the motion. Likewise, parameters independent of the near-zero frequency spectral component often are sensitive solely to the magnitude of the motional asymmetry. These considerations are extended to multispin systems and spin systems where nuclear magnetic relaxation proceeds by competing interactions characterized by nonvanishing interference or cross-correlation functions. In general, one cannot define unambigiously a unique T₁ or T₂ in such a case as the predicted decay is multi-(non)exponential. The spin behavior in such a situation is thoroughly analyzed and many intriguing predictions are presented. It is seen that the failure of a white spectral density approximation or a single exponential decay of the molecular correlation function often leads to predictions of extreme nonexponentiality of the magnetization decay. While the results of these calculations are of general interest, they are especially pertinent for those concerned with biological applications of NMR. Finally, the initial concepts are extended to a discussion of the potentially powerful Perturbed Angular Correlation experiment where it is shown that the coincidence counting rate will in general be influenced by anisotropic modulation of the quadrupolar perturbation. It is emphasized that a conventional interpretation of relaxation data is impregnated with hidden, "extreme-narrowed", reasoning. Extensive figures are provided which not only facilitate experimental application of the calculations, but also provide striking evidence for the caution which must be exercised in any biodynamical interpretation of nuclear spin relaxation. / Science, Faculty of / Chemistry, Department of / Graduate


Tipton, Wilbur John, 1944- January 1972 (has links)
No description available.

Propagators for higher spin particles

Cravey, Robin Lee 08 1900 (has links)
No description available.

The nuclear spins and moments of several radioactive gallium isotopes

Ehlers, Vernon James. January 1960 (has links)
Thesis (Ph. D. in Physics)--University of California, Berkeley, March 1960. / TID-4500 (15th ed.). Includes bibliographical references (p. 112-115).

Nuclear alignment experiments on cerium radioisotopes

Haag, James Norman. January 1961 (has links)
Thesis (Ph.D.)--University of California, Berkeley, 1961. / "UC-34 Physics" -t.p. "TID-4500 (16th Ed.)" -t.p. Includes bibliographical references (p. 111-114).

Polarization of deuterons scattered from He⁴

Trier, Alex, January 1966 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Spins of the 5.03 Mev and 2.14 Mev States in B11 from angular correlation measurements in B10 (dp) B11

Whalen, Brian Austin January 1965 (has links)
An experimental investigation of the spins of the 2.14 (Jɪ) and 5.03 (J) Mev levels in B¹¹ has been made using the B¹º(dp)B¹¹ reaction to populate the 5.03 Mev level in B¹¹ and then studying pɣ and pɣɣ angular correlations to determine the values of J and Jɪ . The theoretical analysis of the angular correlation data is based on a method in which the dp reaction mechanism is represented by a relatively small number of experimentally determined parameters and therefore the resulting spin assignments are not open to the usual criticisms of the use of (sometimes doubtful) nuclear reaction theories for the positive determination of nuclear spins. Using the information gained from this experiment and previous experimental information on the statistical distribution of M1 to E2 multipole mixing ratios it was possible to assign an overwhelming statistical probability in favour of the J = ³⁄₂, Jɪ = ½ spin assignment. These spin assignments are in agreement with previous tentative ones and with the theoretical shell model calculations of Cohen and Kurath. The parameters, determined by this experiment, describing the dp reaction are compared with those calculated using stripping theory and are shown to be in disagreement with both the Butler Plane Wave and Distorted Wave Born approximation calculations. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Page generated in 0.1418 seconds