Application of Symbolic Programming for Atomic Many-Body Theory

In the present paper a symbolic programming method for generation of the expansion–terms expressions of atomic stationary perturbation theory is presented by using Mathematica system. For this purpose the package named as NCoperators was developed. Producing the PT terms, this package accommodates the features of the RayleighSchrödinger perturbation theory, the second quantization method and angular momentum theory. The package is built in such a way that it could be applicable in various areas of theoretical atomic spectroscopy. Many functions of the NCoperators can be easily adapted for users to their own demand by transforming the functions developed easily. The package gives the possibility of generating formulas in a traditional output form. For some quantities the expressions obtained in Mathematica can be converted into C code. Although the NCoperators package was developed for Unix OS, it can be easily adopted for other OS if some of the parameters to be changed.