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A simple variational-perturbational approach to the correlation problem in atoms and molecules

✍ Scribed by L.S. Cederbaum; K. Scho¨nhammer; W. von Niessen

Publisher
Elsevier Science
Year
1975
Tongue
English
Weight
231 KB
Volume
34
Category
Article
ISSN
0009-2614

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✦ Synopsis

A simp!e ansat;: for the gound state of atoms and molecules is proposed which is also suitable for large internuclear dis-tanc~ where pertrxbation theory breaks down. In its simplest form, where only doubly+xcited configurations are included, the ansatz leads to 97.3% of the exact correhtion energy of Hz0 calculated in the doubly-zxcited configurational space with the same basis set. The calculrltcd correlation energy for N2 shows the correct behaviour as a function of internuclear distance.

Much work has been invested in finding appropriate approaches to calculate ground state energies of atoms

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