In
chemistry, a
molecular orbital (
MO) is a
mathematical function describing the wave-like behavior of an
electron in a
molecule. This function can be used to calculate chemical and physical properties such as the probability of finding an
electron in any specific region. The term
orbital was introduced by
Robert S. Mulliken in 1932 as an abbreviation for
one-electron orbital wave function. At an elementary level, it is used to describe the
region of space in which the function has a significant amplitude. Molecular orbitals are usually constructed by
combining atomic orbitals or
hybrid orbitals from each
atom of the molecule, or other molecular orbitals from groups of atoms. They can be quantitatively calculated using the
Hartree–Fock or self-consistent field (SCF) methods.