Electric quadrupole and hexadecapole moments for X2CCX2, X = H, F, Cl, Br, and I*

Abstract

AbstractWe have calculated electric quadrupole and hexadecapole moments for ethene, tetrafluoroethene, tetrachloroethene, tetrabromoethene, and tetraiodoethene. A large basis set of [9s6p5d2f/5s4p2d] size is thought to provide reference near‐Hartree–Fock results for the electric multipole moments of ethene: Θxx=1.34 and \documentclass{article}\pagestyle{empty}\begin{document}$\Theta_{zz}=1.53\ ea_{0}^{2}$\end{document} for the quadrupole Φxxxx=−17.38, Φyyyy=20.29, and \documentclass{article}\pagestyle{empty}\begin{document}$\Phi_{zzzz}=-17.04\ ea_{0}^{4}$\end{document} for the hexadecapole moment (with z as the CC axis and the molecule on the xz plane). The electron correlation correction to the above values is estimated from coupled cluster calculations as Θxx=−0.12 and \documentclass{article}\pagestyle{empty}\begin{document}$\Theta_{zz}=-0.34\ ea_{0}^{2}$\end{document} for the quadrupole and Φxxxx=1.26, Φyyyy=−1.30, and \documentclass{article}\pagestyle{empty}\begin{document}$\Phi_{zzzz}=1.80\ ea_{0}^{4}$\end{document} for the hexadecapole moment. For the halogenated ethenes we have obtained the following quadrupole moment values from second‐order Mø ller–Plesset perturbation theory calculations: Θxx=−1.14 (C2F4), 1.94 (C2Cl4), 3.61 (C2Br4), 6.84 (C2I4) and Θzz=−1.04 (C2F4), −0.41 (C2Cl4), −0.15 (C2Br4), −0.87 (C2I4) \documentclass{article}\pagestyle{empty}\begin{document}$ea_{0}^{2}$\end{document}. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002