The

    "./rho0-to10800-topo500.tbl"
    "./rho1-to10800-topo500.tbl"

files contain spherical harmonic coefficients of the zero- and first-order 
polynomial density coefficients of the lunar crust as represented by Eq. (4) of 
Bucha (2025).

The coefficients were derived from the 3D linear crustal density model of 
Goossens et al. (2020) using the

    LIN_L250-650_TC40_rho.grd
    LIN_L250-650_TC40_grad.grd

grids.  First, the grids of Goossens et al. (2020) was transformed into the 
representation required by Eq. (4) of Bucha (2025) using Eq. (45) of Bucha 
(2025).  The "rS" term in Eq. (45) of Bucha (2025) was obtained by the surface 
spherical harmonic synthesis of

    "../topo/Moon_LDEM128_shape_pa_11519.tbl"

up to degree 500.  Finally, the grids of "rho0" and "rho1" were harmonically 
analyzed up to degree 10800 to mitigate aliasing.

The

    "./rho0-to10800-topo5400.tbl"
    "./rho1-to10800-topo5400.tbl"

files are similar to

    "./rho0-to10800-topo500.tbl"
    "./rho1-to10800-topo500.tbl"

with the difference being in the degree, up to which "rS" was expanded.  In 
this case, "rS" was expanded to degree 5400.

The file structure follows the CHarm's "tbl" file format (see 
"https://www.charmlib.org").  The coefficients are "4pi"-fully-normalized and 
exclude the Condon--Shortley phase factor.

NOTE 1:  The coefficients depend on the truncation degree of the lunar shape 
         "rS" and they must always be used with the same topography expanded up 
         to the same truncation degree.

NOTE 2: To get the density, both sets of coefficients ("rho0" and "rho1") must 
        always be used together.  Using only "rho0" will *not* yield laterally 
        variable density of the lunar crust.  See Bucha (2025) for details.

REFERENCES:

Bucha, B. 2025.  Spectral gravity forward modelling of 3D variable densities 
    using an arbitrary integration radius with application to lunar topographic 
    masses.  Journal of Geodesy, 99:31 
    https://doi.org/10.1007/s00190-025-01951-9

Goossens S., Sabaka T. J., Wieczorek M. A., Neumann G. A., Mazarico E., Lemoine 
    F. G., Nicholas J. B., Smith D. E., Zuber M. T. (2020) High-resolution 
    gravity field models from GRAIL data and implications for models of the 
    density structure of the Moon's crust. Journal of Geophysical Research: 
    Planets 125:e2019JE006086, https://doi.org/10.1029/2019JE006086$