Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Adiabatic connection forms in density functional theory: H(2) and the He isoelectronic series
AU - Peach, Michael J. G.
AU - Miller, Adam M.
AU - Teale, Andrew M.
AU - Tozer, David J.
PY - 2008/8/14
Y1 - 2008/8/14
N2 - Full configuration interaction (FCI) data are used to quantify the accuracy of approximate adiabatic connection (AC) forms in describing two challenging problems in density functional theory-the singlet ground state potential energy curve of H(2) in a restricted formalism and the energies of the helium isoelectronic series, H(-) to Ne(8+). For H(2), an exponential-based form yields a potential energy curve that is virtually indistinguishable from the FCI curve, eliminating the unphysical barrier to dissociation observed previously with a [1,1]-Pade-based form and with the random phase approximation. For the helium isoelectronic series, the Pade-based form gives the best overall description, followed by the exponential form, with errors that are orders of magnitude smaller than those from a standard hybrid functional. Particular attention is paid to the limiting behavior of the AC forms with increasing bond distance in H(2) and increasing atomic number in the isoelectronic series; several forms describe both limits correctly. The study illustrates the very high quality results that can be obtained using exchange-correlation functionals based on simple AC forms, when near-exact data are used to determine the parameters in the forms. (C) 2008 American Institute of Physics.
AB - Full configuration interaction (FCI) data are used to quantify the accuracy of approximate adiabatic connection (AC) forms in describing two challenging problems in density functional theory-the singlet ground state potential energy curve of H(2) in a restricted formalism and the energies of the helium isoelectronic series, H(-) to Ne(8+). For H(2), an exponential-based form yields a potential energy curve that is virtually indistinguishable from the FCI curve, eliminating the unphysical barrier to dissociation observed previously with a [1,1]-Pade-based form and with the random phase approximation. For the helium isoelectronic series, the Pade-based form gives the best overall description, followed by the exponential form, with errors that are orders of magnitude smaller than those from a standard hybrid functional. Particular attention is paid to the limiting behavior of the AC forms with increasing bond distance in H(2) and increasing atomic number in the isoelectronic series; several forms describe both limits correctly. The study illustrates the very high quality results that can be obtained using exchange-correlation functionals based on simple AC forms, when near-exact data are used to determine the parameters in the forms. (C) 2008 American Institute of Physics.
KW - SYSTEMS
KW - 2-ELECTRON
KW - ATOMS
KW - HYDROGEN MOLECULE
KW - PERTURBATION-THEORY
KW - METALLIC SURFACE
KW - ELECTRON-DENSITIES
KW - GROUND-STATE
KW - EXCHANGE-CORRELATION POTENTIALS
KW - CORRELATION-ENERGY
U2 - 10.1063/1.2965531
DO - 10.1063/1.2965531
M3 - Journal article
VL - 129
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 6
M1 - ARTN 064105
ER -