[mesa-users] Metal mass fractions from chem_def

[Ehsan Moravveji]

Dear MESA users,
I’m puzzled with one of the simplest algorithms in MESA, and it lies in chem_def.
To get metal mass fractions and their names, I call init_chem_tables() and init_chem_element_main_iso_names(). 
Take the AGSS09_element_zfrac() as an example case here.
Then, I simply print out the mass fractions of the first 10 elements along with their names like:

    do i = 1, 10
      print*, i, chem_element_main_iso_name(i), AGSS09_element_zfrac(i) * AGSS09_zsol
    enddo

which prints out:

           1 h1         0.0000000000000000     
           2 he4        0.0000000000000000     
           3 li7          9.8868449352536482E-006
           4 be9        1.2836802705967007E-005
           5 b11        1.5399319917545207E-005
           6 c12        1.7108187719009966E-005
           7 n14        1.9951313489314419E-005
           8 o16        2.2789740466457099E-005
           9 f19         2.7061557458749972E-005
          10 ne20       2.8744211726926869E-005

Simply looking at the initial abundances of these elements in number fraction (e.g. lines 1550 onward), one simply notices that e.g. Carbon is more than 5 orders of magnitude more abundant (in number) than Lithium. However, when I compare this expectation with the same mass fraction ratio in the list above, I do not see this difference! That’s why I’m puzzled here.
I wonder if I’m missing something very basic here. 

Can anyone please enlighten me how to correctly get metal mass fractions?

Best wishes
Ehsan.