[en] Analytic expressions are derived for the hybrid-type two-centre matrix elements of the one-electron dipolar coupling operator between Slater atomic orbitals. The method used is of wide applicability. The matrix elements of interest are written in terms of a generalized form of overlap integral. The overlap integrals are evaluated using the convolution theorem/contour integration technique. Computational results are discussed and times given. (author)

[en] In order to justify the mathematical postulate of a distribution of correlation times, the concept of time-dependent correlation times is introduced. The time dependence arises because molecules may change shape during nuclear relaxation. The model may be used to explain qualitatively the field dependence of the temperature dependence of ¹³C T₁ values in isopropyl alcohol. (Auth.)

[en] Deuterium quadrupole coupling constants (DQCC) for deuterium nuclei in a variety of bonding situations have been obtained by means of semiempirical molecular orbital wavefunctions in the INDO approximation. All integrals of the operator entering the electronic contributions have been included with no approximations in their evaluation. Analytical expressions are tabulated for the relevant two-center integrals; three-center integrals were obtained by numerical integration techniques. The factors responsible for the very strong dependence of deuterium QCC on internuclear distance, and the relative constancy of the parameters for a given bonding situation are discussed with regard to the types of terms which enter the integral expressions and the molecular electronic distributions. Some interesting and possibly useful predictions are also included in the tabulated results; the DQCC for the bridging deuterium in diborane is predicted to have a value of -110 kHz, which may be the first negative value for a DQCC; the effects of hydrogen bonding can be significant, the result of lengthening of the D--X bond on hydrogen bond formation

[en] The use of magnetic resonance imaging, in the demonstration of internal human anatomy and in the diagnosis of disease, has the major advantages that the technique is non-invasive, does not require the use of ionizing radiation and that it can demonstrate neurological and cardiovascular lesions that cannot be diagnosed easily by other imaging methods. The first magnetic resonance images of humans were obtained in Australia in October 1985 on the research instrument of the Queensland Medical Magnetic Resonance Research Centre, which is based at the Mater Hospital in Brisbane

[en] Abstract only