A new reciprocal space based method for the calculation of long range forces in clusters, wires, and surfaces has been introduced. The technique allows existing plane-wave based density functional theory, Ewald or Ewald/SPME software to be modified easily to study such systems. The method corrects the error introduced by employing an infinitely replicated periodic system to model a system with fewer than three periodic dimensions. This is particularly important because energy differences between systems with different total charge are ill-defined in infinitely replicated periodic systems[2, 3]. In contrast, the new methodology can be used to determine quantities of interest such as cluster ionization energies and energy differences between neat surfaces and surfaces with defects or adsorbates. The new technique was employed in conjunction with both DFT-based ab initio and classical MD methods on model as well as realistic problems with arbitrary total charge. It was found to be efficient and to yield accurate energy differences forces and absolute energies. Finally, the new methodology was observed to eliminate rather large errors in the small systems that are typically examined using an ab-initio approach as well as more subtle errors that arise in the large systems typically studied using empirical force fields.