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  • 1
    Electronic Resource
    Electronic Resource
    Combined bond-polarization basis sets for accurate determination of dissociation energies (1989)
    Springer
    Theoretical chemistry accounts 76 (1989), S. 195-209 
    Details
    ISSN: 1432-2234
    Keywords: Basis set ; Basis set superposition error (BSSE) ; Bond functions ; Site-site function counterpoise (SSFC) ; Pairwise additive function counterpoise (PAFC) ; Successive reaction counterpoise (SRCP)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The effect of bond functions on the basis set superposition error (BSSE) is investigated at both SCF (self consistent field) and correlated levels for a number of basis sets using the pairwise additive function counterpoise (PAFC), the site-site function counterpoise (SSFC), and the newly proposed successive reaction counterpoise method (SRCP). BSSEs using bond functions are shown to be roughly twice those without bond functions, whereas the latter may still be quite sizeable. The addition of f functions dramatically decreases the bond function BSSE. The results obtained support the empirical decision in our earlier papers to neglect BSSE altogether.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527473
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  • 2
    Electronic Resource
    Electronic Resource
    Combined bond polarization function basis sets for accurate ab initio calculation of the dissociation energies of AHn molecules (A=LI to F) (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 152-162 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: An alternative route toward developing basis sets for post-Hartree-Fock calculations, the hybrid bond polarization function method, is investigated. Two new basis sets, denoted 6-31G(d, p)+ B and 6-31 + G(d,p)+B, are defined for the first-row hydrides. The dissociation energies of the first-row hydride species in their respective ground states are computed using full fourth-order Møller-Plesset theory, and compared with results obtained with large polarized basis sets containing no bond functions. It is shown that results are competitive even with basis sets as large as 6-311++G(3df,3pd), while computation times are reduced by a factor of 4 to 20. On empirical grounds, the basis set superposition error should be neglected entirely.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540100203
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  • 3
    Electronic Resource
    Electronic Resource
    Combined bond-polarization basis sets for accurate determination of dissociation energies. II. Basis set superposition error as a function of the parent basis set (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 875-886 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The effect of the parent basis set on the basis set superposition error caused by bond functions is investigated systematically. An important difference between BSSE at the SCF and correlated levels is pointed out. Three new basis sets are defined, denoted 6-311 + G(d,p)B, 6-311 + G(2d,p)B, and 6-311 + G(2df,p)B. BSSE for the first-row hydrides seems to increase uniformly with increasing atomic number of the central atom. Expansion of the valence part of the basis set from 6-31G to 6-311G, as well as adding f functions, has a significant effect on the BSSE. Additional BSSEs incurred by bond functions are less than or equal to 1 kcal/mol for the 6-311 + G(2df,p)B basis set. For the dissociation energies of the first-row hydride species, agreement with experiment within only a few kcal/mol can be obtained even without resorting to isogyric reaction cycles. For high-quality calculations, adding bond functions seems to have definite advantages over expanding the polarization space beyond the [2d1f] level.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540100704
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  • 4
    Electronic Resource
    Electronic Resource
    A critical comparison of MINDO/3, MNDO, AM1, and PM3 for a model problem: Carbon clusters C2-C10. An ad hoc reparametrization of MNDO well suited for the accurate prediction of their spectroscopic constants (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 12 (1991), S. 52-70 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Dissociation energies and potential energy surface features for the carbon clusters C2 to C10 are compared with ab initio or experimental results for the semiempirical methods MINDO/3, MNDO, AM1, and PM3. Quite surprisingly, MINDO/3 gives a rather good account of the various structures and electronic states, unlike the other three methods. MINDO/3 tends towards systematic overestimates of binding energies, the other methods to systematic gross underestimates. Reparametrization of the diatomic parameters α, βs, and βp for exact reproduction of the experimental data for C3 results in much improved values for binding energies, but fails to correct the state splittings. Also reparametrizing Uss, Upp, ζs, and ζp to reproduce the ab initio linear-rhombic energy difference in C4 results in a much improved description of the other states. For the linear structures, computed harmonic frequencies with the latter parameters are in surprisingly good agreement with experimental or correlated ab initio data, where available; experimental values are consistently overestimated by about 40 cm-1. Other results are comparable in quality to good ab initio treatments. The experimental IR bands at 2128 and 1892 cm-1, formerly assigned to C9, should be reassigned to linear C7. The intense 1997 cm-1 feature almost certainly belongs to C9; bands at 1952 and 1197 cm-1 both belong to linear C6. Tentative assignments of bands in the 1600-1850 cm-1 region to various cyclic structures of C6, C8, and C10 have been made. As such, this suggests a new and promising procedure for the theoretical study of large molecules in general, and of large clusters in particular.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540120107
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  • 5
    Electronic Resource
    Electronic Resource
    Ab initio study of the proton affinity of a number of ortho-substituted pyridines (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 346-357 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The proton affinity, dipole moment, and first vertical ionization potential of a number of ortho-mono-substituted pyridines are computed at the restricted Hartree-Fock level, using a number of different basis sets. Some approximations concerning the geometry, the force constants, and the basis set superposition error are introduced. The effect of both the basis set and the approximations is investigated systematically. Two nonstandard basis sets, 4-31G(*) and 4-31+G(*), in which polarization functions are only applied to heteroatoms, are defined. A qualitative explanation for the effects of electron correlation on the proton affinity is given and underbuilt with the results of some MP2 calculations. While accuracy is maintained, computational cost is reduced very substantially.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540100308
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical study of the proton affinities of 2-, 3-, and 4-monosubstituted pyridines in the gas phase by means of MINDO/3, MNDO, and AM1 (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 10 (1989), S. 449-467 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Proton affinities (PAs) of 2-, 3-, and 4-monosubstituted pyridines in the gas phase are calculated using the MINDO/3, MNDO, and AM1 methods. The following substituents are considered: F, Cl, CN, CH3, CF3, CHO, NO2, NH2, N(CH3)2, OCH3, and SCH3. The results are compared with experimental values. It is found that all MINDO/3 PAs are ca. 6% too high (mean value) compared to the experimental results; on the other hand, the MNDO values are ca. 7% too low (mean value). However, a much better agreement has been observed for the AM1 method where the theoretical values are only ca. 2.4% too low (mean value). Correlations between the calculated proton affinities on one hand and the charges on the acid H atom and Hammett constants on the other hand are studied. Particularly good linear relationships are found for the 4-monosubstituted compounds within the AM1 formalism.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540100403
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  • 7
    Electronic Resource
    Electronic Resource
    Theoretical study of the proton affinities of 2-, 3-, and 4-monosubstituted phenolate ions in the gas phase by means of MINDO/3, MNDO, and AM1 (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 11 (1990), S. 269-290 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Proton affinities (PAs) of 2-, 3-, and 4-monosubstituted phenolates in the gas phase are calculated using the MINDO/3, MNDO, and AM1 methods. The following substituents are considered: H, F, Cl (only MNDO and AM1), CN, CH3, OH, NO2, OCH3, COOH, and NH2. The results are compared with experimental values (high-pressure mass spectroscopy) at 600 K. The MINDO/3 method overestimates the experimental PAs with a mean percentual error of ca. 4.3%. The MNDO results agree much better with the experimental values and are only ca. 1.3% too high. However, the best agreement is observed for the AM1 method, where the mean percentual error is only ca. 0.69% (in absolute value). The greatest disagreement is found for 2-hydroxyphenolate (ca. +2.0%) and 2-carboxyphenolate (ca. +2.7%). The PA of 2-nitrophenolate is underestimated by ca. 1.6%. Correlations between the calculated proton affinities on the one hand, charge densities on the acid H atom of the phenols, charges on the O atom in the phenolate ions, and substituent parameters on the other hand are studied. Particularly good linear relationships are found for the 3- and 4-monosubstituted compounds within the AM1 formlism. For the 2-substituted phenolates, only the AM1 method is satifactory. As a general conclusion, the AM1 method appears to be distinctly superior to MNDO for the calculation of PAs, and definitely superior to MINDO/3.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540110302
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