Inside Cover, Volume 113, Issue 17



An understanding of molecular periodicity that has a basis in quantum states is highly desirable. The article by Ray Hefferlin, Jonathan Sackett, and Jeremy Tatum on page 2078 (DOI: 10.1002/qua.24469) explores this possibility through specific studies of diatomic systems that successively approach the formation of a rare-gas molecule. Molecules echo atomic periodicity, because properties for series of molecules follow a periodic behavior defined by molecular magic numbers. In the case of many band systems, it is the ratio of the force constants of the upper and lower states that determines the periodic behavior.