SYMMETRY-ADAPTED BASES OF MATRIX SPACES APPLIED TO QUANTUM-CHEMISTRY

Generalized normalized irreducible tensorial matrices (GNITM) are obta ined by symmetry-adapting the matrix basis of a matrix space that is i nvariant to reducible representations of a unitary group. Like previou sly defined normalized irreducible tensorial matrices (NITM), the GNIT M are orthonormal under the trace and transform irreducibly under G. T he GNITM are useful for constructing matrices having specific behavior under G. In particular, an Hamiltonian matrix is invariant under the symmetry group of the corresponding physical system and is expressed a s a linear combination of invariant GNITM. The orbital model of ammoni a is treated as an example.