Accuracy and limitations of the pseudopotential method |
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Authors: | Tse -Chiang Chang Peter Habitz W H Eugen Schwarz |
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Institution: | (1) Lehrstuhl für Theoretische Chemie der Universität Bonn, Wegeler Str. 12, D-5300 Bonn, Federal Republic of Germany;(2) Fachbereich Chemie der Gesamthochschule, D-5900 Siegen 21, Federal Republic of Germany;(3) Present address: Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, China |
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Abstract: | Molecular model potential calculations have been performed within the SCF approximation on nine di- and triatomic molecules from the first row of the periodic table. We compare the molecular constants with ab initio SCF values and with model potential results obtained by other authors. Our results are accurate to a few per cent. The three most significant approximations in molecular model potential theory are: 1) The molecular model potential is the sum of atomic model potentials; 2) The atomic model potential is energy-independent; 3) The electron interaction model operator is l/r
12. We arrive at the following general conclusions concerning these approximations: 1) The first approximation does not hold for strongly ionic molecules and for some highly excited molecular states. 2) Approximations 2 and 3 cancel to a large extent in molecules as they do in atoms, except in the case where approximation 1 breaks down. 3) Although various model- and pseudo-potentials yield reasonable results for atoms, not all of them are suitable for molecular calculations. |
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Keywords: | First row elements di- and triatomic molecules consisting of " target="_blank">gif" alt="sim" align="MIDDLE" BORDER="0"> Pseudopotential method |
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