After addressing the comments that my mentors gave for step 1 of the DDEC6 algorithm, I have written a small PR that calculates step 2 reference charges for DDEC6. Basically, it uses the reference charges that were obtained in step 1 and interpolates the radial densities of the ion/atoms with ceiling(qref) and that with floor(qref). Then, using the updated radial proatom densities, reference charges are again evaluated.

When compared with the values obtained in chargemol, I was able to observe quite close value (about 8% difference – between .3840 and .4161 for hydrogen in water molecule). In the test suite, the tolerance was set to be a bit larger than this because horton proatomic charges are used in the test suite.

Tomorrow, I am expecting to write a function that conditions the proatomic densities to obtain ρcond for each atom. This should take care of step 3 in the DDEC6 algorithm.