# The Thermodynamics of Chromatography - Interactions Between the Atoms of Hydrogen, Carbon, Chlorine and Bromine and an Exclusively Dispersive Stationary Phase > Page 29

(DG'_{Cl}) is associated with interaction
between a chlorine atom and the stationary phase,

and (DG'_{Br}) is
associated with interaction between a bromine atom and the stationary phase.

Equations (9)
to (18) can be used (with the aid of a simple, iterative computer program) to
solve for (DG'_{H}), (DG'_{C}), (DG'_{Cl}) and (DG'_{Br}).
However, it is clear that equations (9) to (11) can be replaced by a general
equation for the chlorine substituted methanes, likewise equations (12) to (14)
can be replaced by a general equation for the bromine substituted methanes and
equations (15) to (17) can be replaced by a general equation for the chlorine
substituted bromomethanes. Similarly, equations (15) and (18) are members
of the bromine substituted monochloromethanes.

Thus, the general equation for the chlorine substituted methanes will be,

(19)

the general equation for the bromine substituted methanes will be,