(a) Instead of (15.23), the following equation has been proposed for extrapolation from SCF aug-cc-pVQZ and aug-cc-pV5Z energies to the CBS limit [A. Karton and J. M. L. Martin, Theor. Chem. Acc., 115, 330 (2006)]:

Where L is the largest orbital-angular momentum l value that appears in the basis set, For H2O, aug-cc-pVQZ and aug-cc-p5Z SCF energies at optimized geometries are - 6.066676 and -76.068009 hartrees. Find the CBS limit predicted by this extrapolation formula.
(b) Equation (15.88) can also be used with the aug-cc-pV5Z and aug-cc-pV6Z Hartree- Fock energies. The HF/aug-cc-pV6Z geometry-optimized energy for H2O is -76.068153 hartrees. Find the HF/CBS limit predicted by (15.88) and the aug-cc-pV5Z and aug-cc- pV6Z SCF energies. Compare the CBS values found in this problem to the estimate in Table 15.2.
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Escr(aug-n) = EsCF(m) + A(L + 1)e_9VL ROH/A Basis Set STO-3G, 7 3-21G, 13 Minimal STO, 7 6-31G*, 19 6-31G, 25 cc-pVDZ, 24 Energy /Ehp/D Reference CCCBDB CCCBDB Pitzer, Merrifield CCCBDIB CCCBDIB CCCBDB K. S. Kim et a 6-311++G(2d.2p), 47 76.057 2.02 06.3 CCCBDIB CCCBDIB Dunning et al. Rosenberg et a. (5s4p2d/3slpo 39 76.064 2.00 0. CCCBDB CCCBDB Amos K. S. Kim et a (13s8p4d2f/8s4p2d), 13 76.0676 1.94 06.3 Bakken et al. Bakken et al. Cortez et al. θ 1.71 100.0 0.989 -75.586 2.39 107.70 0.967 1.92 100.3 0.990 2.20 105.5 0.947 2.15 106.0 0943 76.027 .0404.6 0.946 0.940 1.99 106.0 0.941 1.93 06.3 0.941 2.08 106.6 0.941 0.940 -76.0655 97 106.2 0.940 1.94 106.30.940 106.3 0.940 0.940 74.966 -75.705 76.011 76.024 cc-pVTZ, 58 aug-cc-pVTZ, 92 [6s5p2d/3s1pl,43 -76.058 一76.061 cc-pVQZ, 115 aug-cc-pVQZ, 172 60667 .94 106.3 [8s6p4d2f/6s3pld, 112 76.0675 cc-pV5Z, 201 aug-cc-pV5Z, 287 cc-pV6Z, 322 aug-cc-pV6Z, 443 special -76.0678 196 106.33 0.9396 76.0680 4 106.340.9396 -76.06810 1.95 106.34° 0.9396 76.06815 4 106.34 0.9396 106.340.9396 Pahl, Handy Estimated Hartree-Fock energy Nonrelativistic fixed-nuclei energy Experimental value.s 76.06817 76.0683 -76.438 764 1045 0.9573 104.5f 0.9578 -76.480e