from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or relating to a molecule that has three or more atoms as constituents.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. (of a molecule or ion) consisting of three or more atoms
from the GNU version of the Collaborative International Dictionary of English
- adj. Having more than one atom in the molecule; consisting of several atoms.
- adj. Having a valence greater than one.
from The Century Dictionary and Cyclopedia
- In chem., noting elements or radicals which have an equivalency greater than two; also, noting compounds having three or more hydroxyl groups, in which hydrogen is easily replaceable by other elements or radieals without otherwise changing the structure of the original compound: thus, glycerol is a polyatomic alcohol.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. of or relating to a molecule made up of more than two atoms
Sorry, no etymologies found.
Personally, I would call a polyatomic molecule only inelastic if its vibrations (or electrons) were excited, but as I say, this is debatable.
Following up on chriscolose's response: in dense gases you get "collision-induced absorption" - a pair of molecules can absorb a photon while they are close enough to be exerting forces on each other you can think of the two colliding diatomic molecules as forming a very short lived polyatomic molecule.
Any polyatomic molecules of interest in combustion would completely decompose even at much lower temperatures.
We also developed a means of producing fragments of polyatomic molecules (free radicals such as benzyl and methoxy) by directing a pulsed laser into a specially designed pulsed supersonic nozzle, and studying these cooled in the supersonic beam.
The detailed physics of rotating polyatomic molecules with spin is extremely complex.
Now we could study at least small polyatomic molecules with at the same penetrating level of detail previously attained only for atoms and diatomics.
With AP2 we quickly succeeded in setting the world's record for rotational cooling of a polyatomic molecule (0.17 K).
I told him that wouldn't be cold enough - the lowest rotational temperature reported for a polyatomic molecule in a supersonic beam that I was aware of at that time was 30 K still way too hot to achieve the simplification we needed.
Medicines Control Council for approval to carry out legitimate tests on the controversial procedure, known as oxytherapy, or polyatomic apheresis.
He and his associates have determined the structures of a large number of diatomic and polyatomic molecules, including the structures of many free radicals difficult to determine in any other way (among others, those of free methyl and methylene).