A+E Networks. On this day in 1969, Americaâs first automatic teller machine (ATM) makes its public debut, dispensing cash to customers at Chemical Bank in Rockville Center, New York.
This modification of the energy levels of a hydrogen atom due to a combination of relativity and spin-orbit coupling is known as fine structure.
Chlorophyll a - Molecular structure. 1  The molecular structure of chlorophyll a consists of a chlorin ring, whose four nitrogen atoms surround a central magnesium atom, and has several other attached side chains and a hydrocarbon tail. 2  Chlorophyll a contains a magnesium ion encased in a large ring structure known as a chlorin.