Fortran modules for conversion between Euler coordinates of two rigid rotor molecules and Euler coordinates of their isotopomers. Can be used to convert the Potential Energy Surface of the main isotopomer to rare isotopomers. See the comments in the source files for more detailed description.

isotopologue_coordinates_conversion.f90 is the main conversion module.

constants.f90 and lapack.f90 are auxiliary modules.

conversion_test.f90 is an example driver for the conversion module.

Compilation is straightforward, see compile.sh for an example.