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Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/3829

Title: Abinitio study of the structure, infrared-spectra, and heat of formation of c4
Authors: MARTIN, Jan
FRANCOIS, Jean-Pierre
GIJBELS, R
Issue Date: 1991
Publisher: AMER INST PHYSICS
Citation: JOURNAL OF CHEMICAL PHYSICS, 94(5). p. 3753-3761
Abstract: The lowest-lying 1A(g) and 3-SIGMA-g- states of C4 have been studied using basis sets including f functions, quadratic configuration interaction, and full fourth-order Moller-Plesset perturbation theory with multiple spin projection. Basis set effects on the linear-cyclic separation have been found to be fairly significant. Use of the 6-311G* and [5s3p1d] basis sets leads to qualitatively different conclusions; this problem is remedied by expansion of the polarization space. At the highest level of theory considered, the cyclic structure lies about 1 kcal/mol below the linear structure. A G1-type estimate of its heat of formation at 0 K of 249.6 kcal/mol is proposed. This value is in disagreement with the generally quoted experimental values, but in good agreement with third-law values by Drowart et al. [J. Chem. Phys. 31, 1131 (1959)] corrected for improved partition functions. Geometries and harmonic frequencies are reported. It is tentatively suggested that a matrix ir band at 1284 cm-1 may belong to cyclic C4; to aid experimentalists in confirming or rejecting this assignment, theoretical isotope shifts are reported.
Notes: LIMBURGS UNIV CENTRUM,DEPT SBM,B-3610 DIEPENBEEK,BELGIUM.MARTIN, JML, UNIV INSTELLING ANTWERP,INST MAT SCI,DEPT CHEM,UNIV PLEIN 1,B-2610 WILRIJK,BELGIUM.
URI: http://hdl.handle.net/1942/3829
DOI: 10.1063/1.459747
ISI #: A1991FA77800052
ISSN: 0021-9606
Type: Journal Contribution
Appears in Collections: Research publications

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