Date of Award


Publication Type

Doctoral Thesis

Degree Name




First Advisor

Drake, G.


Physics, Molecular.




A multiple basis set extension of the doubled basis set methods originally developed by Drake et al.$\sp5$ for Hylleraas type calculations in two-electron systems is applied to the 1s$\sp2$2s $\sp2$S ground state of Li. An 1134 term basis set containing all sums of powers of the distance coordinates up to seven yields an improvement of two orders of magnitude in the accuracy of the best previous upper bound to the non-relativistic ground state energy, $-$7.478 059 54 a.u.$\sp{12}.$ The upper bound obtained is $-$7.478 060 312 a.u., with an extrapolated energy $-$7.478 060 326 (10) a.u. This is in agreement with a new semi-empirical estimate of this value which is approximately 10 microhartrees above published semi-empirical estimates of the non-relativistic ground state energy. New calculations of the relativistic and QED corrections are required to resolve the discrepancy. A value for the Fermi contact term of 2.9054 (3) a$\sbsp{0}{-3}$ is calculated, compared with the experimental value of 2.9061(3) a$\sbsp{0}{-3}.$Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1991 .M354. Source: Dissertation Abstracts International, Volume: 53-01, Section: B, page: 0353. Chairman: G. W. F. Drake. Thesis (Ph.D.)--University of Windsor (Canada), 1991.