Calibration of rectangular atomic force microscope cantilevers

A method to determine the spring constant of a rectangular atomic force mic roscope cantilever is proposed that relies solely on the measurement of the resonant frequency and quality factor of the cantilever in fluid (typicall y air), and knowledge of its plan view dimensions. This method gives very g ood accuracy and improves upon the previous formulation by Sader [Rev. Sci. Instrum. 66, 3789 (1995)] which, unlike the present method, requires knowl edge of both the cantilever density and thickness. (C) 1999 American Instit ute of Physics. [S0034-6748(99)04210-0].