TY - JOUR
T1 - Upper and lower bounds for ground-state energies in the helium isoelectronic sequence
AU - Abdel-Raouf, M. A.
PY - 1979/7
Y1 - 1979/7
N2 - The formula of Rayleigh [1] and Ritz [2] is used for determining upper bounds for E0's, E1's and E2's of nine members of the helium isoelectronic sequence. A rough estimation for the lower bounds of E0's is carried out using Temple's relation [3]. The calculations show that a 50-dimensional expansion space can be adjusted to obtain results in good agreement with those of other authors and to confine the exact E0's in gaps of the order of 10-5.
AB - The formula of Rayleigh [1] and Ritz [2] is used for determining upper bounds for E0's, E1's and E2's of nine members of the helium isoelectronic sequence. A rough estimation for the lower bounds of E0's is carried out using Temple's relation [3]. The calculations show that a 50-dimensional expansion space can be adjusted to obtain results in good agreement with those of other authors and to confine the exact E0's in gaps of the order of 10-5.
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U2 - 10.1016/0378-4363(79)90011-1
DO - 10.1016/0378-4363(79)90011-1
M3 - Article
AN - SCOPUS:0018495880
VL - 97
SP - 103
EP - 106
JO - Physica B: Physics of Condensed Matter & C: Atomic, Molecular and Plasma Physics, Optics
JF - Physica B: Physics of Condensed Matter & C: Atomic, Molecular and Plasma Physics, Optics
SN - 0378-4363
IS - 1
ER -