FIGURE 2.

Theoretical dispersion curve of the transverse shear mode of a membrane according to Eq. 1. The mode frequencies f₀ = ω₀/2π and damping Γ versus mode wave vector q for the parameter γ₀ = 1 mN/m, ρ = 1 mg/ml, and η = 1 mPa are shown at different surface viscosities γ′: 0 nNs/m (—), 1 nNs/m (- - -), and 10 nNs/m (⋯). The damping Γ splits after the bifurcation point into the slow damping mode Γ₁ and the fast damping mode Γ₂. The fast damping Γ₂ cut off at the same value to which the slow damping Γ₁ converges asymptotically.