2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/80687Effect of external periodic force on an oscillatory order in a reaction diffusion system (Gierer Meinhardt model) has been investigated. The 2:1 resonance situation is found susceptible for the generation of a band of phase instabilities. These phase instabilities, captured on multiple time scales, produces a mismatch between the oscillation frequency of reacting species.1 text file and 1 figurePattern Formation and Solitonstext