as I understand there isn't any straight way to get an rdf of atoms from the center of mass or a coordinate of specific atoms in lammps. I wonder if anyone know any trick or way to get it in lammps or as post processing in VMD.
1) Define spherical bins using the "compute chunk/atom" command with the center point you desire.
2) Calculate the number density of each spherical bins using the "fix ave/chunk" and write its results to your desire file.
3) You can normalize the results by dividing them by the number density of your simulation box.
and also if you want to calculate it for specific atom types, you can define a group for that type and change the groups used for the compute and fix commands.