Definition of Franck–Condon in US English:

Franck–Condon

noun

Chemistry
  • Attributive Designating or relating to the principle that an electronic transition in an atom is so fast that the configuration of the atomic nucleus is likely to remain unchanged during it, but that a change from one nuclear vibrational level to another will be more likely the more the two vibrational wave functions overlap; especially in "Franck–Condon principle", "Franck–Condon factor".

Origin

1920s; earliest use found in Proceedings of the National Academy of Sciences of the United States of America. From the names of James Franck, German physicist, who first described the principle, and his student Edward U. Condon, U.S. physicist, who expressed Franck's theories in terms of quantum mechanics.

Pronunciation

Franck–Condon

/frɑːŋkˈkɒndən/