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lsgen and lsgenf

The new version of the genclf program has the same design as GENCL (see Froese Fischer and Liu  [#!FL!#]) but has been extended to arbitrarily-filled f-shells. The latter required some change in notation. The subroutines that changed a lot are the LVAL, SYMB and COUPLD. The rest of the subroutines are either unchanged or the changes are not substantial. The LVAL subroutine is extended with a possibility to convert the symbols O and Q into its corresponding quantum number and in SYMB to convert the quantum numbers 11 and 12 into its corresponding symbol. In the COUPLD subroutine the data blocks containing the term characteristics are enlarged.

Input and output data of the new version are the same as before. One needs only to take into account that the classification of terms of the $f$ subshell is more complicated than for $s$, $p$, $d$ subshells. For the classification of $f$-subshell terms the characteristics (2$S$+1) (multiplicity), $L$ (total orbital momentum), and $\nu$ (seniority) are not sufficient. Here we use a notation $^{(2S+1)}L^{Nr}$ for the classification of an $f$-subshell. The $Nr$ is single character, which corresponds the group labels $\nu WU$. It is identical to Gaigalas and Froese Fischer [#!GFa!#] and P5 [#!__5172__method5__5172__!#]. The value $Nr$ is found in Table 1 of P5 [#!__5173__method5__5173__!#] where all terms for $f$-subshells are presented. In most cases, $Nr$ appears to be a digit, but since it is a single character, the single letter $A$ is used instead of the number 10. While in all the other cases the two-digit numbers n in $cfg.inp$ file encode the following $n$ = CHAR(n+ICHAR('0')) (see [#!FL!#]). For example, the values of the principal quantum number $n$ or multiplicity $(2S+1)$ may exceed 9. On most systems the list of integers, $\{10,11,12,13,14,15\}$ map into the list of characters, $\{:,;,<,=,>\}$. The CSF list if output to the file cfg.inp.

When $f$-shells are restricted to two electrons, the earlier LSGEN program may be used [#!lsgen!#]. This program has been extended to arbitrarily filled f-shells, and is known as lsgenf but has not been documented. Like LSGEN, the CSF list that is output is left in clist.out. For simple cases, gencl is easier to use interactively. Unlike genclf where $^{10}D$ on SUN systems must be entered as $^:D$, lsgenf allows the user to specify $10D$, although the output file will adhere to the proper convention.

The program maintains an order for the orbitals, determined from the order in which an orbital is first encountered. Thus, with a reference set of 4s(2)3d(1) and an active set of 3d,4s,4p the file cfg.inp will not have orbitals in a consistent ordering. The ordering of orbitals in the reference set, the active set, and the virtual set should always be the same in the sense that one orbital will always appear before or after another. Sometimes this is referred to as the after relation.


next up previous contents
Next: lsreduce Up: Utility programs Previous: lines   Contents
2001-10-11