Publication title Fundamentals of Laser Spectroscopy for Atoms and Diatomic Molecules Purdue author Robert Lucht Publisher Cambridge University Press Publication date December 2024 About the book ...

The showcase example for such complete change in behaviour is the rotational structure in homonuclear diatomic molecules under isotope substitution mentioned above.

Bromine is one of only two liquid elements. Iodine is solid. They exist as diatomic molecules - they have two atoms in each molecule. As you go down the group the halogens become less reactive.