Comment on "Optical Response of Strongly Coupled Metal Nanoparticles in Dimer Arrays"

I have recalculated the extinction spectra of aggregates of two silver nanospheres shown in Figs. 2 and 3 of the paper by J. J. Xiao, J. P. Huang, and K. W. Yu [Phys. Rev. B 71, 045404 (2005)]. I have used the approximate method of images according to the formulas published in that reference and an exact numerical technique. I have found that the three sets of data those I have obtained by the method of images, the numerical results, and the results published in the reference in question do not coincide. In this Comment, I discuss the reasons for these discrepancies and the general applicability of the method of images to the quasistatic electromagnetic problem of two interacting nanospheres.