snt format

In NuclearToolkit.jl, input/output interactions are in the so-called snt format (or its binary form). The snt format is one used in widely-used shell-model code KSHELL. If you specify the option tbme_fmt="snt.bin" for Chiral EFT interactions, the output becomes binary form. The integers are in Int16 for a,b,c,d,J (single particle index and total-J of two-body matrix elements, TBMEs) and Int64 for others, and the floating point numbers for TBMEs are in Float32 (by default).

Here is an example of w.snt. The comments are not written in the outputs of NuclearToolkit.

! "!" denote comment line
!
! model space
! proton-orbit, neutron-orbit, proton core, neutron core
3 3 8 8
! orbit n l j tz
1 0 2 3 -1 ! 1 = p 0d_3/2
2 0 2 5 -1 ! 2 = p 0d_5/2
3 1 0 1 -1 ! 3 = p 1s_1/2
4 0 2 3 1 ! 4 = n 0d_3/2
5 0 2 5 1 ! 5 = n 0d_5/2
6 1 0 1 1 ! 6 = n 1s_1/2
! one-body interaction
! number of lines, method1
6 0
! i j <i|V|j>
1 1 1.64658
2 2 -3.94780
3 3 -3.16354
4 4 1.64658
5 5 -3.94780
6 6 -3.16354
! two-body interaction (TBME)
! # of lines, method2 A mass dependence factor
158 1 18 -0.30000
! i j k l J <i,j| V | k,l>_J
1 1 1 1 0 -2.18450
1 1 1 1 2 -0.06650

For free space interactions, output of chiEFTint, they have V2n3n and Vpp terms in addition to the VNN term:

...
! i j k l J <i,j| VNN | k,l>_J <i,j| V2n3n | k,l>_J <i,j| Vpp | k,l>_J
  1    1    1    1     0     -6.4492081719      0.0000000000   -0.0000000000e+00
  1    2    1    2     0     -1.9671496992      0.0000000000    5.0000000000e-01
...