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Unformatted text preview: 10.675 LECTURE 9 RICK RAJTER 1. Today Finish basis sets zeta basis set BSSE explanation of test of basis sets correlation (CI and MP) 2. Basis Sets r n Zeta = ( (2 ) n +1 / 2 n 1 e ao Y l ( , ) [(2 n )!] 1 / 2 ) r Zetas CC-PV*Z, AUC-CC-PV*Z AUG diffuse functions * variable... D double, T triple, Q quadruple, 5 quintuple. double means use 2 gaussians to describe each set p polarization cc correlation consistent (electrons optimized) to reproduce atoms energies (CISD). 3. Basis Set Superposition Error - BSSE localized LCAO 2 atoms A and B... Individually, they are an incomplete system (which we will say is a combination of the two). incompleteness if compensated in the molecule due to the other molecule. The isolated incomplete basis sets complete/help each other. The problem: Bond energy over predicted due to change in completeness from A +B AB independent of method....
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- Spring '03