dynamic spring constant

Chris_G posted on Mon, Oct 22 2012 9:24 PM

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Hi all. There have been a number of papers recently that have discussed how the dynamic spring constant can potentially be significanly larger than the static spring constant for AFM cantilevers (e.g. Sader et al. REVIEW OF SCIENTIFIC INSTRUMENTS 83, 103705 (2012))

The difference can be as much as 10% depending on the cantilever geometery. Therefore depending on the calibration technique used the spring constant may have to adjusted. My question is does the thermal nosie method measure the dyanmic or static spring constant ? I realise there are corrections (1.11 for beam shaped and 1.14 for V-shaped) that must be applied to the technique concerning the optical lever sensitivity calibration since the static deflection is different to oscillating motion. However I'm still unsure whether a further correction is necessary given the recent work on dynamic and static spring constants.  

Thanks, Chris Gibson.