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Volumn 105, Issue 39, 2001, Pages 9040-9048

A concise set of large, symmetric molecules for evaluation of modern computational methods

Author keywords

[No Author keywords available]

Indexed keywords

HYBRID DENSITY FUNCTIONAL (HDFT) METHODS;

EID: 0035807658     PISSN: 10895639     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp011482j     Document Type: Article
Times cited : (40)

References (63)
  • 26
    • 85033640874 scopus 로고    scopus 로고
    • note
    • A survey of the Journal of the American Chemical Society for the first quarter of the year 2000 found 63 papers reporting quantum calculations on compounds containing only main group elements. B3LYP calculations were employed for geometry optimization in 47 of these papers. Often more than one basis set was employed for calculations of geometry in each paper, but most highly represented were variations of the 6-31G basis set (59 examples), with the 6-31G(d) (23 examples), 6-31+G(d) (14), and 6-31+G(d,p) (13) basis sets being the most common by far.
  • 28
    • 85033636140 scopus 로고    scopus 로고
    • note
    • The best fits for the overlap of the experimental and calculated structures were determined by using the OFIT function in Siemens SHELXTL,20 and all non-hydrogen atoms were used for the fitting.
  • 32
    • 85033646195 scopus 로고    scopus 로고
    • note
    • My own interest in these computational problems began with the observation that HDFT calculations systematically overestimated the bond distances in the polycyclic aromatic hydrocarbon hexabenzotriphenylene, so that the calculated diameter of this large, propeller-shaped molecule (C42H2-0 was fully 0.1 A greater than that of an accurate, low-temperature X-ray structure.24 Low-level Hartree-Fock (HF) calculations gave better overall geometries than the HDFT methods for the simple reason that the HF bond length errors were randomly dispersed about the experimental values. The overestimation of bond lengths by HDFT methods is hardly unknown,25'26 but certainly unadvertised.
  • 37
    • 85033634822 scopus 로고    scopus 로고
    • note
    • Another virtue of high-symmetry structures is that the data may be of better quality. Although I am unaware of any studies establishing such a correlation for small-molecule determinations, Dickerson and coworkers29 have found it to be true for macromolecules, noting that among all the available self-complementary B-DNA crystal structure analyses, those crystals exhibiting the highest resolution are the ones that minimally perturb the intrinsic 2-fold internal symmetry of the molecule. Highest resolution ... is obtained in the monoclinic space group C2, where the molecular symmetry coincides with a true crystallographic 2-fold axis... Where this is forbidden by anisotropic crystal packing, a price is paid in terms of increased disorder within the crystal structure and lower resolution.
  • 39
    • 0000483279 scopus 로고
    • The citations for the 20 crystal structures used as experimental, references in this paper are listed here (alphabetically by the CSD refcode). BAHRIL: Korp, J. D.; Bemal, I.; Watkins, S. F.; Fronczek, F. R. Tetrahedron Lett. 1981, 22, 4767-4770.
    • (1981) Tetrahedron Lett. , vol.22 , pp. 4767-4770
    • Korp, J.D.1    Bemal, I.2    Watkins, S.F.3    Fronczek, F.R.4
  • 60
    • 0003422019 scopus 로고    scopus 로고
    • Wavefunction, Inc., Irvine, CA.
    • SPARTAN Version 5.0, Wavefunction, Inc., Irvine, CA.
    • SPARTAN Version 5.0
  • 62
    • 85033646285 scopus 로고    scopus 로고
    • note
    • Hehre and Lou26 go so far as to say, in a discussion of various available DFT methods, While 'cost' must be taken into account, it is difficult to recommend the pB/DN and pB/DN models (or limiting Becke3LYP models) for the task of geometry determination where secondrow elements are involved.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.