Orbitals

The stationary states a particle can have in a given potential distribution.  Since any such state has a constant energy, the particle's [[wave function]] Y must satisfy HY = EY for some E >= 0.  Here H is the [[Hamiltonian]] operator; since it is [[linear]], this becomes an [[eigenvector]] equation on the space of all states.  Thus orbitals are just the energy [[eigenstates]] of the particle.

Of particular importance are [[atomic orbitals]] and [[molecular orbitals]], the stationary states of electrons in atoms and molecules.