  A new method, 'Configurationally-Resolved-Super-Transition-Arrays', for
calculation of the spectral absorption coefficient in hot plasmas is presented.
In the new method, the spectrum of each Super-Transition-Array is evaluated as
the Fourier transform of a single Complex Pseudo Partition Function, which
represents the exact analytical sum of the contributions of all constituting
unresolved transition arrays sharing the same set of one-electron solutions.
Thus, in the new method, the spectrum of each Super-Transition-Array is
resolved down to the level of the (unresolved) transition arrays. It is shown
that the corresponding spectrum, evaluated by the traditional
Super-Transition-Arrays (STA) method [A. Bar Shalom, J. Oreg, W.H. Goldstein,
D. Shvarts and A. Zigler, Phys. Rev. A 40, 3183 (1989)], is just the coarse
grained Gaussian approximation of the
Configurationally-Resolved-Super-Transition-Array. A new computer program is
presented, capable of evaluating the absorption coefficient by both the new
configurationally resolved and the traditional Gaussian Super-Transition-Arrays
methods. A numerical example of gold at temperature 1keV and density 0.5
gr/cm^{3}, is presented, demonstrating the simplicity, efficiency and accuracy
of the new method.

Atomic Physics