protomolecule

Noun

protomolecule (plural protomolecules)

1. A collection of unstably bound atoms that has the potential to form a molecule if the structure can shed sufficient energy.
   • Molecular hydrogen is by the way a very difficult species to form in the gas phase by radiative association of H atoms, mainly because the protomolecule formed in this way is vibrationally highly excited and cannot get rid of the energy excess to enter inside the potential well and reach stability...1991, Ezio Bussoletti, G. Strazzulla, Solid-state astrophysics: 27 June-7 July 1989, →ISBN, page 385
   • This is a consequence of the fact that the protomolecule, just formed in a high vibrational level, has to release quickly (roughly in a time comparable with its vibrational period) an energy excess of about four and a half electronvolt.1998, Julián Chela Flores, F. Raulin, Exobiology, →ISBN, page 287
2. A relatively simple molecule from which a more complex molecule is derived.
   • It is most probable that all matter is simply the allotropic expression of one element and that the protomolecule is the union of the positively and negatively electrified etheric corpuscle.1912, George Frederick Shrady, Thomas Lathrop Stedman, Medical Record
   • Another example is the technique developed at NRC for synthesizing the insulin protomolecule.1982, Canada Parlement House of Commons Standing Committee on Miscellaneous Estimates, Minutes of Proceedings and Evidence of the Standing Committee on Miscellaneous Estimates