Graphical Unitary Group Approach (GUGA)
Encyclopedia
Graphical Unitary Group Approach (GUGA) is a technique
used to construct Configuration state function
s (CSFs) in
computational quantum chemistry
. As reflected in its name, the
method uses the mathematical properties of the unitary group
.
The foundation of the unitary group approach (UGA) can be traced to the work of
Moshinsky. Later,
Shavitt
introduced the graphical aspect (GUGA) drawing on the earlier work of
Paldus.
Computer programs based on the GUGA method have been shown to be
highly efficient.
offering certain performance advantages over the older, sometimes
called traditional, techniques for CSF construction. However traditional methods can offer other
advantages such
as the ability to handle degenerate symmetry point groups, such as
.
used to construct Configuration state function
Configuration state function
In quantum chemistry, a configuration state function , is a symmetry-adapted linear combination of Slater determinants. A CSF must not be confused with a configuration.-Definition:...
s (CSFs) in
computational quantum chemistry
Quantum chemistry
Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems...
. As reflected in its name, the
method uses the mathematical properties of the unitary group
Unitary group
In mathematics, the unitary group of degree n, denoted U, is the group of n×n unitary matrices, with the group operation that of matrix multiplication. The unitary group is a subgroup of the general linear group GL...
.
The foundation of the unitary group approach (UGA) can be traced to the work of
Moshinsky. Later,
Shavitt
introduced the graphical aspect (GUGA) drawing on the earlier work of
Paldus.
Computer programs based on the GUGA method have been shown to be
highly efficient.
offering certain performance advantages over the older, sometimes
called traditional, techniques for CSF construction. However traditional methods can offer other
advantages such
as the ability to handle degenerate symmetry point groups, such as
.