Photoexcitation of molecules adsorbed on a nm-sized metal particle can be appreciably enhanced due to plasmon oscillations. The price for this enhancement is characterized by the ratio of the rates of light absorption by plasmons and an adsorbed molecule. We present the equations making it possible to estimate this ratio for monochromatic light and also in the case when the photon frequency is distributed over an interval which is wider than the plasmon damping width. (c) 2007 Elsevier B.V. All rights reserved.