Perspective on New developments in molecular orbital theory -: !Roothaan CCJ (1951) Rev Mod Phys 23:69-89

This paper reviews the title article by Clemens Roothaan and the huge impact that his paper has had in modern chemistry. In his paper Roothaan converts the molecular Schodinger equation into a matrix equation by systematically introducing the linear combination of atomic orbitals-molecular orbital approximation and by invoking the variational principle.