Work function change measurements (Delta Phi) combined with temperature programmed desorption (TPD) were employed to study layer growth mechanism and the CH3Cl dipole-dipole interactions on Ru(001), over the temperature range of 97 K-230 K. The activation energy for desorption (E-a) and the molecular dipole moment (mu) both decrease from 55.9 kJ/mol and 2.44 D, at the zero coverage limit, to 38.6 kJ/mol and 1.27 D, at one monolayer. This coverage dependence originates from strong dipolar lateral repulsion among neighbor CH3Cl molecules. Using a model introduced by Maschhoff and Cowin (MC) [J. Chem. Phys. 101, 8138 (1994)], the isolated adsorbed molecule's dipole moment, mu(0) (2.35 D) and polarizability alpha(8.1x10(-24) cm(3)), were extracted from TPD data. These values agree very well with mu(0) (2.12 D) and alpha(9.2x10(-24) cm(3)) obtained from work function change measurements by employing the same MC model. The ability to simulate both TPD and work function change data over a wide coverage range within the framework of a single electrostatic model has been demonstrated. It enabled better understanding of fine details of surface dipolar interactions.