Atomic orbital , the letters associated with those numbers are K, L, M, N, O, ... respectively. The simplest atomic orbitals are those that are calculated for systems with a single electron, such as the hydrogen atom. An atom of any other element ionized down to a single electron is very similar to hydrogen, and the orbitals take the same form. In the Schrödinger equation for this system of one negative and one positive particle, the atomic orbitals are the eigenstates of the Hamiltonian operator for the energy. They can be obtained analytically, meaning that the resulting orbitals are products of a
Alan (given name) what is today Brittany, France. An early figure who bore the name was St Alan, a 5th-century bishop of Quimper. This saint became a cult figure in the Brittany during the Middle Ages. Another early bearer of the name was St Alan, a 6th-century Cornish saint, who has a church dedicated to his memory in Cornwall (for example see St Allen, a civil parish in Cornwall named after this saint). Today the use of the given name (and its variants) is due to its popularity among the Bretons who imported the name to England, to Cornwall, and later to Ireland.