Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 1413-1419 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The F2 ground state potential curve has been computed near re by means of the MCSCF, CI(SD), MR-CI(SD) and the recently proposed CPF method. Extensive sets of polarization functions including up to five d sets, three f sets, and one g set have been used to study the convergence of the total energy of De, and re for these methods on basis set extension. SCF and MCSCF show a similar behavior and are practically converged on the 2d1f level. Convergence is much slower for methods which include external correlation, such as CI(SD), MR-CI(SD), CPF. The largest calculation performed—MR-CI(SD) for a [6 4 2 1] basis—included 280 076 configuration state functions, and yields De and re with an accuracy of 0.07 eV and 0.015 a.u. These remaining errors are attributed mainly to the neglect of g functions. The present results provide detailed information concerning the relative importance of polarization functions which can be ordered as: d(1)〉d(2)(approximately-greater-than)f(1)〉d(3) for SCF and MCSCF and d(1)〉f(1)(approximately-greater-than)d(2)〉g(1)(approximately-greater-than)f(2)(approximately-greater-than)d(3) for methods including external correlation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 116 (1994), S. 11251-11255 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 107 (1985), S. 6494-6498 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 75 (1989), S. 99-110 
    ISSN: 1432-2234
    Keywords: Carbosilanes ; Structure ; Bonding ; Population analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Results of extended basis set treatments on the SCF level of theory are reported for all C-chlorinated, Si-chlorinated, symmetrically C- and Si-chlorinated silaethanes, and some chlorinated 1,3-disilapropanes. These molecules are considered as models for carbosilane compounds in general. Computed geometric structure constants are in good agreement with experiment as far as a comparison is possible. The stability and reactivity of molecules considered is discussed by means of computed bond distances, isodesmic reaction energies, and especially by results of population analysis. Si-chlorination yields a stabilization of the Si-C skeleton in carbosilanes whereas C-chlorination reduces this stability to a large extent.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 75 (1989), S. 1-10 
    ISSN: 1432-2234
    Keywords: Phosphanes ; Structure of phosphanes ; Ring strain ; Lone pair interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molecules PH3, P2H4, P3H5, P3H3, P4H4, and P5H5 were treated at the SCF level using basis sets of DZP quality. Computed structure constants and energies indicate high stability for P5-ring systems and small ring strain for P3- and P4-ring systems. The computed values for the strain are 28 and 18 kJ/mol for P3H3 and P4H4, respectively. Neighbouring P atoms with transconfigured lone pairs are favoured in the monocyclic phosphanes considered in this work, as shown by the energy difference of about 10 kJ/mol between trans and cis configured lone pairs, and the shortening of P-P distances by about 2 pm for trans configured P atoms.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 1551-1553 
    ISSN: 0947-3440
    Keywords: Fullerene C70 ; Cyclopropanation ; C70 Bisadducts ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The biscyclopropanation of C70 with bromomalonate anions shows a strong preference for three regioisomers, which can be separated by column chromatography. The structures of the three regioisomers were determined by 13C-NMR spectroscopy. The two cyclopropanation reactions take place on opposite hemispheres of C70.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: μ4-S(B2H5)2, (H2BSH)2, 1,2-(HS)2B2H4: New Thiaboranes from the Reaction of Diborane with Hydrogen Sulfide. - Theoretical Investigation of the StructuresThe new and unstable compounds 1λ3,3λ3,2λ4,4λ4-dithiadiboretane (H2BSH)2 (1), the isomer 1,2-dimercaptodiborane 1,2-(HS)2B2H4 (2), μ4-thiabis(diborane) μ4-S(B2H5)2 (3), μ2-mercaptodiborane μ2-HS(B2H5) (4), dimercaptoborane HB(SH)2 (5), and polymers are formed in the reaction of B2H6 and H2S, with or without toluene, in a pressure tube at -15 to -10°C. 11B-NMR shifts and 1J(11B1Ht,b) coupling constants convey structural information. Structure data of 1, 3, and 4 have been determined by SCF calculations. According to these results, 1 exists as a mixture of planar Z and E isomers, 3 has a pyramidal structure; the BSB unit in 3 and 4 has some central or open three-center character.
    Notes: B2H6 und H2S reagieren im Einschlußrohr (mit oder ohne Toluol als Lösungsmittel) bei -15 bis -10°C unter H2-Entwicklung zu den neuen, instabilen Verbindungen 1λ3,3λ3,2λ4,4λ4-Dithiadiboretan (H2BSH)2 (1) sowie dem dazu isomeren 1,2-Dimercaptodiboran 1,2-(HS)2B2H4 (2), μ4-Thiabis(diboran) μ4-S(B2H5)2 (3), μ2-Mercaptodiboran μ2-HS(B2H5) (4), Dimercaptoboran HB(SH)2 (5) und Polymeren. Die Strukturen dieser Verbindungen werden durch die 11B-NMR-Parameter belegt. Aus SCF-Rechnungen erhielten wir die Strukturparameter für 1, 3 und 4. 1 besteht danach aus einer Mischung planarer Z- und E-Isomeren, 3 besitzt pyramidale Struktur; in 3 und 4 liegen zentrale bzw. offene 2-Elektronen-3-Zentren-BSB-Bindungen vor.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 6 (1985), S. 200-208 
    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 CGTO integral evaluation, SCF, SCF-gradient, integral transformation, and MR-CI (SD) steps of the COLUMBUS system of programs have been adapted for the CYBER 205. A description is given of our efforts and the partly heavy modifications necessary to exploit the potential of this supercomputer and to avoid its shortcomings. Typical timings are reported, vector and scalar performance are compared.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...