Dynamic Modes Flashcards
How is the cantilever driven in dynamic modes of AFM?
Driven at or close to its resonant frequency.
What benefit does dynamic mode have?
The force is primarily in the vertical axis so damage or movement due to lateral forces is reduced.
How does the sensitivity of the system depend on Q, k and omega?
Increasing Q and omega and lowering k all increase the sensitivity of the system.
What fundamentally limits the force we can detect with an AFM?
Thermal noise.
What must be done to be able to ‘see’ a molecule?
It must be bound to the surface sufficiently to stay still for the time scale of the measurement and not to be moved by tip sample forces.
How does tip convolution affect the image of a molecule?
The width seen in the image is approximately the width of the probe at the height of the molecule. The molecule images the tip.
