Equilibrium structures of heterocyclic molecules with large principal axis rotations upon isotopic substitution

Jean Demaison, A. Császár, Laurent D. Margulès, Heinz Dieter Rudolph

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Equilibrium structures, re, of the heterocyclic molecules oxirane, furazan, furan, ethylene ozonide, and 1,3,4-oxadiazole have been determined using three different, somewhat complementary techniques: a completely experimental technique (rm), a semiexperimental technique (re SE, whereby equilibrium rotational constants are derived from experimental effective ground-state rotational constants and corrections based principally on an ab initio cubic force field), and an ab initio technique (re BO, whereby geometry optimizations are usually performed at the coupled cluster level of theory including single and double excitations augmented by a perturbational estimate of the effects of connected triple excitations [CCSD(T)] using quadruple-ζ Gaussian basis sets). All these molecules are asymmetric tops with the moment of inertia I c much larger than the other two moments of inertia, Ia and Ib. Molecules of this shape experience a large rotation of the principal axis system upon certain isotopic substitutions. For such isotopologues it is difficult to obtain a good structural fit to the semiexperimental moments of inertia Ia and Ib, which may significantly reduce the accuracy of the re SE structural parameters. The origin of this difficulty is explained. For the heavy-atom skeleton of these molecules it was possible to determine a rather accurate empirical mass-dependent structure without a priori knowledge of the equilibrium structure.

Original languageEnglish
Pages (from-to)14078-14091
Number of pages14
JournalJournal of Physical Chemistry A
Volume115
Issue number48
DOIs
Publication statusPublished - Dec 8 2011

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moments of inertia
Substitution reactions
substitutes
Molecules
molecules
ozonides
Ethylene Oxide
furans
musculoskeletal system
Ground state
field theory (physics)
excitation
ethylene
Atoms
optimization
ground state
Geometry
estimates
geometry
atoms

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Equilibrium structures of heterocyclic molecules with large principal axis rotations upon isotopic substitution. / Demaison, Jean; Császár, A.; Margulès, Laurent D.; Rudolph, Heinz Dieter.

In: Journal of Physical Chemistry A, Vol. 115, No. 48, 08.12.2011, p. 14078-14091.

Research output: Contribution to journalArticle

Demaison, Jean ; Császár, A. ; Margulès, Laurent D. ; Rudolph, Heinz Dieter. / Equilibrium structures of heterocyclic molecules with large principal axis rotations upon isotopic substitution. In: Journal of Physical Chemistry A. 2011 ; Vol. 115, No. 48. pp. 14078-14091.
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