dc.contributor.author Cann, Natalie Mary. en_US dc.date.accessioned 2014-10-21T12:36:54Z dc.date.available 2014-10-21T12:36:54Z dc.date.issued 1993 en_US dc.identifier.other AAINN93638 en_US dc.identifier.uri http://hdl.handle.net/10222/55378 dc.description Explicitly-correlated wavefunctions are generated for the n$\sp1$S, n$\sp3$S, n$\sp1$P, n$\sp3$P, n$\sp1$D, and n$\sp3$D states, where n $\le$ 6, of the helium isoelectronic series from He to Ne$\sp{8+}$. These 100 term wavefunctions are optimized variationally and the resulting energies are the best available for 180 of the 261 states considered. In addition to the energy, each wavefunction is assessed by its asymptotic behaviour and by the degree to which it satisfies the virial theorem, electron-electron cusp condition, and electron-nucleus cusp condition. These criteria assess the overall wavefunction behaviour as well as the behaviour at small and large interparticle separations. en_US dc.description The wavefunctions are used to systematically study the variation of the charge and intracule densities with respect to spin multiplicity, nuclear charge Z, degree of excitation n, and angular momentum L. The accuracy of a screened hydrogenic density model is determined for each state and ion. The Z-, L-, and n-dependence of six correlation coefficients is systematically studied. These coefficients emphasize radial and angular correlation in the inner, intermediate, and outer regions of the electron distribution. From the explicitly correlated wavefunctions and near Hartree-Fock quality self-consistent-field wavefunctions, Coulomb holes and radial density holes are obtained for the 3$\sp1$D and 3$\sp3$D states of the ions from He to Ne$\sp{8+}$. en_US dc.description For He, generalized oscillator strengths (GOS) are calculated for S $\to$ S, S $\to$ P, and S $\to$ D transitions originating from the 1$\sp1$S, 2$\sp1$S, and 2$\sp3$S states. Although, the GOS for each transition are calculated for over sixty momentum transfer (K) values, several small-K and large-K GOS expansion coefficients are also provided. For each ion, dipole oscillator strengths (DOS) are calculated for 55 S-P and 40 P-D transitions. These DOS are more accurate than previous values for 739 of the 855 transitions considered. Quadrupole oscillator strengths (QOS) are also obtained for 44 S-D transitions of each ion. en_US dc.description For extrapolation to higher Z, 1/Z expansion coefficients are calculated for energies and correlation coefficients of each state, and each DOS transition. en_US dc.description Thesis (Ph.D.)--Dalhousie University (Canada), 1993. en_US dc.language eng en_US dc.publisher Dalhousie University en_US dc.publisher en_US dc.subject Chemistry, Physical. en_US dc.title An accurate treatment of helium-like ions: Properties and wavefunctions. en_US dc.type text en_US dc.contributor.degree Ph.D. en_US
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