In 2000, Carver Mead introduced a time-symmetrical theory of energy exchange between two atoms, building on the Transactional Interpretation of Quantum Mechanics by John Cramer in 1986. In 2020, Cramer and Mead developed the theory further, proposing a conceptual path integral formulation by which energy could be completely transferred over long distances, and showing that this theory can explain the Einstein-Podolsky-Rosen paradox, the Hanbury–Brown–Twiss effect, and the Freedman-Clauser entanglement experiment. In this paper, we develop the theory further, proposing a specific formulation of the interaction between Emitter and Absorber atoms, in which the energy density is proportional to the root-mean-square of the product of retarded and advanced four-vector potential waves, and show how this interaction efficiently and completely transfers energy from the Emitter atom to the Absorber atom over arbitrary distances. We use Mach’s Principle and conservation of energy to find the proportionality constant by matching the mean transition time constant for all possible absorbers in the universe to the mean transition lifetime computed from Fermi’s Golden Rule, leading to a complete solution with no adjustable parameters. The solution represents the exchange of energy between two atoms, valid over 26 orders of magnitude in Emitter-Absorber distance, from about 0.52 m to the radius of the Hubble Sphere 1.27×1026m. We define this Wave-Particle Model as the product of a retarded emitter vector potential wave and an advanced absorber vector potential wave, which exhibits the particle-like properties of losslessly carrying energy at the speed of light in a straight line from emitter atom to absorber atom in a vacuum in the absence of gravity.