ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Ab initio accurate all-electron relativistic molecular orbital Dirac-Fock self-consistent field calculations are reported for the linear symmetric XeF2 molecule at various internuclear distances with our recently developed relativistic universal Gaussian basis set. The nonrelativistic limit Hartree-Fock calculations were also performed for XeF2 at various internuclear distances. The relativistic correction to the electronic energy of XeF2 was calculated as ∼ -215 hartrees (-5850 eV) by using the Dirac-Fock method. The dominant magnetic part of the Breit interaction correction to the nonrelativistic interelectron Coulomb repulsion was included in our calculations by both the Dirac-Fock-Breit self-consistent field and perturbation methods. The calculated Breit correction is ∼6.5 hartrees (177 eV) for XeF2. The relativistic Dirac-Fock as well as the nonrelativistic HF wave functions predict XeF2 to be unbound, due to neglect of electron correlation effects. These effects were incorporated for XeF2 by using various ab initio post Hartree-Fock methods. The calculated dissociation energy obtained using the MP2(full) method with our extensive basis set of 313 primitive Gaussians that included d and f polarization functions on Xe and F is 2.77 eV, whereas the experimental dissociation energy is 2.78 eV. The calculated correlation energy is ∼ -2 hartrees (-54 eV) at the predicted internuclear distance of 1.986 Å, which is in excellent agreement with the experimental Xe - F distance of 1.979 Å in XeF2. In summary, electron correlation effects must be included in accurate ab initio calculations since it has been shown here that their inclusion is crucial for obtaining theoretical dissociation energy (De) close to experimental value for XeF2. Furthermore, relativistic effects have been shown to make an extremely significant contribution to the total energy and orbital binding energies of XeF2. © 1995 John Wiley & Sons, Inc.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560550302
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