Surface plasmon resonances in Drude metal cylinders: radius dependence and quality factor

We have studied the dispersion relation of surface plasmon modes in metal cylinders using the Drude model by numerically solving complex eigenfrequencies as a function of the radius. We also studied the quality factor Q of the modes and found that it decays as the radius is increased, and for a small radius there is a maximum value equal to omega(s)/gamma. independent of the mode order (where omega(s) is the Ritchie's surface plasmon frequency and gamma is the damping constant).