Thesis (Ph.D.)--Ohio University, June, 2006. / Title from PDF t.p. Includes bibliographical references (p. 119-128)

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In this thesis, particle- particle angular correlations for reactions in non-zero degree geometry and with non-zero spin nuclei are performed and found to be a valuable tool for spin determination, (d-α) angular correlations in the reaction process ¹⁴N(⁶Li,d)¹⁸F* (α)¹⁴N are measured for three high excited states in ¹⁸F with a ⁶Li beam of 36MeV. Spins and parities for two of the observed states are determined, and in agreement with theoretical predictions, these states are suggested as members of the K^π=1⁺ α-rotational band. The three analysed 9.58MeV 6⁺, 11.2MeV, 14.1MeV 8⁺ states are found to undergo a predominant α-particle decay to the ground state of ¹⁴N. Gamow unbound formalism is carried out for the state descriptions. Angular distributions are measured and analysed under Hauser Feshbach and exact finite range DWBA formalisms. Spectroscopic factors are extracted and compared to shell model predictions, showing a reasonable agreement. (³He-α) and (t-α) angular correlations for the reaction processes ¹⁴N(⁶Li,³He)¹⁷0* (α)¹³C and ¹⁴N(⁶Li,t)¹⁷F* (α)¹³N respectively are measured at 36MeV of ⁶Li. High selectivity is observed for the three particle transfer processes and percentages of the different particle decays for the high populated states are presented. Structureless angular correlations hinder definite spin and parity assignements, but the displacement of the preferred direction observed in the pattern decay gives some information on the range of plausible angular momenta. Shell model calculations are performed for comparison with the experimental data, and this allows tentative spin identifications. EFR EWEA calculations are carried out, providing some confirmation on the spin suggestions. Useful nuclear structure information is obtained for the mass 17 and 18 nuclear states. The particle-particle angular correlation expression for a process where a direct reaction mechanism is involved is reviewed, programmed and used for obtaining the theoretical predictions to be compared to the experimental results.

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The thesis extends the concept of Irreducible Spherical Tensor Operators to spin dynamics problems in Nuclear Magnetic and Quadrupole Resonance Spectroscopy. NQR and solid state NMR deal with spin systems which behave as effective single spins in many, pulsed experiments, or as multispin systems when the dipolar interactions among spins cannot be neglected. The thesis considers problems in both areas. New analytic results are derived in the thesis for pure NQR spectroscopy and for the effect of radiofrequency fields in the presence of electric quadrupolar interaction. Three-pulse experiments are proposed for a spin-5/2 system and quantitative calculations are done for the indirect detection of new observables. Attention is focussed on the usefulness of the full-spin density matrix in all these calculations. In addition the concept of multispin tensors is applied to a system of spin-1/2 nuclei with strong dipolar interactions. This leads to coupled differential equations for correlations among spins for which an iterative solution can be obtained. The solutions are discussed in relation to Free Induction Decay experiments available for $ sp{19}$F nuclei in CaF$ sb2$ crystal.

An orbital dependent local spin density-functional (LSD) scheme with a generated exchange, the LSD GX scheme, has been developed based on the correct normalization conditions of an electron gas. This scheme contains no adjustable parameters; the B$ sb1$, B$ sb2$ and $ alpha sp lim$ are constant for all atoms once the shape of the Fermi hole is chosen. These parameters are rigorously calculated using an unspecified Fermi hole correlation factor and they give an exchange density which reduces exactly to the homogeneous free electron gas one at the high electron density limit. / The LSD GX exchange density is corrected for self-interaction (SI) by splitting the total Fermi hole correlation factor into pure-exchange and self-interaction holes. / These new LSD and SI corrected schemes are compared to each other. They also compare very well theoretically and numerically (total energies and eigenvalues) with other local schemes current in the literature. / New equations for the IP and electronegativities of the atoms in these local schemes are derived which give good results.

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Thesis (Ph.D.) - University of St Andrews, October 2007.