Ra. Peebles et Rl. Kuczkowski, (N2O)(2)center dot SO2: Rotational spectrum and structure of the first vander Waals trimer containing sulfur dioxide, J CHEM PHYS, 112(20), 2000, pp. 8839-8846
The trimer (N2O)(2). SO2 has been studied by Fourier transform microwave sp
ectroscopy. The rotational constants for the normal species are A=1369.1014
(11) MHz, B=1115.5816(11) MHz, and C=730.5790(4) MHz. Five isotopomers of t
he complex have been studied, allowing a determination of its structure. Th
e configuration aligns the centers-of-mass of the three monomers in an appr
oximate equilateral triangle. The monomers twist relative to this plane so
that the two N2O's are intermediate between T-shaped and crossed rather tha
n the usual slipped-parallel planar. The SO2 is oriented so that its oxygen
s are straddling one N2O (similar to the N2O . SO2 dimer), while its sulfur
is closest to the oxygen end of the other N2O. The dipole moment of ((N2O)
-N-15)(2). SO2 was measured, giving mu(a)=0.606(1) D, mu(b)=1.256(2) D, mu(
c)=0.058(2) D, and mu(total)=1.396(2) D. A semiempirical model has been use
d to predict the trimer structure, and comparison is made with this model a
s well as with the dimer N2O . SO2. (C) 2000 American Institute of Physics.
[S0021-9606(00)01520-8].