title: Field shifts and lowest order QED corrections for the ground 1 1S and 2 3S states of the helium atoms.
abstract: The bound state properties of the ground 1 1S(L=0) state and the lowest triplet 2 3S(L=0) state of the 3He, 4He, and infinityHe helium atoms are determined to very high accuracy from the results of direct numerical computations. To compute the bound state properties of these atoms the author applied his exponential variational expansion in relative/perimetric three-body coordinates. For the ground 1 1S(L=0) state and the lowest triplet 2 3S(L=0) state of the 3He, 4He, and infinityHe atoms the author also determined the lowest order QED corrections and the field component of isotopic shift (=field shift). For the 2 3S(L=0) state of the 3He atom the hyperfine structure splitting is evaluated. The considered properties of the ground 1 1S state and the lowest 2 3S state in the 3He and 4He atoms are of great interest in a number of applications.
authors.affiliation: Department of Applied Mathematics, University of Western Ontario, London, Ontario N6A 5B7, Canada.
authors.forename: Alexei M
authors.initials: AM
authors.lastname: Frolov