<p>We present a novel theoretical model of a periodic metal gap metal system within the framework of dual-lengthscale quasiparticle excitations to investigate the surface lattice resonance (SLR) effect. By formulating a driven quantum pseudoforce system, we derive the resonance condition for localized electron excitations in the spillout region. Our analysis demonstrates that the dual-lengthscale character of plasmonic modes enables simultaneous coupling of the driving force to both localized surface plasmons and the surface lattice geometry. To capture this mechanism, we introduce a generalized double-driven pseudoforce model that facilitates hybrid resonance through indirect coupling between the lattice parameter and the driving wavenumber, mediated by gap plasmon excitations. Employing realistic parameters for a periodic array of gold nanoparticles, we explore the hybrid surface lattice resonance condition across a broad range of physical variables. The model predicts the emergence of two distinct resonant peaks: one corresponding to localized surface plasmon resonance at lower driving wavenumbers, and another associated with SLR at higher wavenumbers. In addition, we provide the Wigner distribution and dielectric response functions of gap electrons, offering further insight into the system’s phase-space and dielectric dynamics. This collective quantum approach establishes a comprehensive framework for elucidating the physical mechanisms underlying surface plasmon lattice resonance and its parametric dependence, thereby advancing the design of plasmonic and nano-optical devices with tailored resonance characteristics.</p>