rcsfgenerate silently omitting configurations for j >= 7/2 subshells

[mzmansour]

I was trying to build a jj coupling programe with the same output like GRASP rcsfgenerate90. For subshells with j >= 7/2 the seniority number was added and rcsfgenerate90 output does not have some configurations for example consider we have to get all jj coupling of configuration 5g(5) then I got 639 levels while rcsfgenerate90 have 254 levels. Some of the configurations are missing like ( 5g-( 2) 5g ( 3) with J/p = 1/2+).

I attached the output of both rcsfgenerate90 (as rcsf.txt) and my code (as csf.txt). The output of both runs appear in output.txt file.

Why rcsfgenerate90 miss some configurations?

output.txt rcsf.txt csf.txt

[cffischer]

There are restrictions to the GRASP package that were extended a bit recently. But believe there are no CFP's or coefficients of fractional parentage for unfilled 5g, 5g- sub-shells so, I believe, GRASP only allows occupation numbers of two for 5g, 5g- orbitals. Might be a problem to explore!

[jongrumer]

Yes, this is a limitation as far as I know too. I will close this issue for now, but should be put on our ever-growing to-do list. Thanks for the question @mzmansour and for the reply @cffischer!

[mortenpi]

but should be put on our ever-growing to-do list

That's what the issue tracker is for, so reopening :slightly_smiling_face:

I think there are two actionable points here:

1. Make rcsfgenerate throw an error or, minimally, produce a warning when configurations are being omitted.
2. A much more complex issue is properly supporting g and higher subshells with arbitrary number of electrons. It might be worth opening a separate issue for that.

[jongrumer]

Great, I agree with @mortenpi. No 1 is simple, no 2 requires an extension of the angular libraries by @gaigalas right?

[CYChenFudan]

@jongrumer @cffischer @mortenpi It is interesting that the RESTRICTION in the CPC paper for grasp2018 [CPC 237, 184-187 (2019)] stated that the restriction on j=9/2 was removed: "The tables of reduced coefficients of fractional parentage used in this version are limited to sub-shells with j ≤ 9/2 [3]; occupied sub-shells with j > 9/2 are, therefore, restricted to a maximum of two electrons." I did test runs using the CODE downloaded from CPC Lib. The restrictions exist.