Subject: Floppy Molecules
Apologies for coming into this late in the day. There is a
fairly large literature on "floppy" or "non-rigid"
I think that the already-mentioned reference to Bunker's
book "Molecular Symmetry and Spectroscopy" covers the
most important work in the field.
But there is much else. 2 references I have to hand are:
H. Frei, A. Bauder, H. H. Gunthard, "The Isometric Group of
Nonrigid Molecules", in Top. Curr. Chem., Vol. 81, Large
Amplitude Motion in Molecules, I, p3, (1979)
"Symmetries and Properties of Non-Rigid Molecules", Ed. J.
Maruani and J. Serre, Studies in Physical and Theoretical
Chemistry, 23, Elsevier, Amsterdam, (1982).
There is also a recently published book-volume edited by
Yves Smeyers "Structure and Dynamics of Non-Rigid Molecular
Systems", Kluwer, 1994, in which I have an article with
some perspectives on how to treat the problem of inter-
conversions between minima of different geometries/symm-
One small point on the use of the term "fluxional": I have
also seen it used to refer to inorganic molecules where no
valence tautomerisation occurs, the archetypal example of
which is PF_5. The Smith-Berry internal rotation which
interconverts all the indistinguishable Trig-bipy isomers
doesn't change any bonding very much.
Richard G. A. Bone, PhD.
Terrapin Technologies, Inc.
750-H Gateway Blvd.
South San Francisco
Tel. +1 (415) 244 9303
FAX +1 (415) 244 0705
E-mail rgab "-at-" trpntech.com