Coherent Resonance for Rate Oscillations During CO Oxidation on Pt(110) Surfaces: Interplay Between Internal and External Noise

Effects of noise on rate oscillations during CO oxidation on Pt(110) surface were investigated, both theo-retically and numerically, by focusing on the interplay of internal noise (IN) due to stochasticity in reaction events, and external noise (EN) resulting from parameter perturbation. The surface is divided into cells of variable size which are assumed to be well mixed, and we consider the behavior inside a single cell. At-tention is paid to parameter regions subthreshold of the deterministic Hopf bifurcation, where noise can induce stochastic oscillations, the signal-to-noise ratio (SNR) of which shows a maximum with the variation of noise intensity, known as coherent resonance (CR). By stochastic normal theory, we show that IN and EN contribute in a weighted additive way to an effective noise that lead to CR, such that SNR shows a ridge shape in the D-1/N plane, where D and 1/N measures the strength of EN and IN, respectively. It is shown that for too large IN (EN), CR behavior with EN (IN) no longer exists. Numerical simulations show good agreements with the theoretical results