| 摘要 |
Interatomic forces are measured with subatomic lateral resolution by in situ calibrated non-contact and passively thermal drift compensated atomic force microscopy in aqueous or generally liquidous environment; interatomic forces acting between distinct electronic orbitals of front-most tip atom and opposing sample atom can be quantitatively measured with subatomic lateral resolution. Calibration standard is a CaCO3-crystal, which undergoes a well defined pressure induced phase transition from the calcite to the aragonite crystal lattice structure providing an accurate independent force anchor point for the AFM's force versus distance curve. Furthermore, an independent actual tip-sample-distance d calibration is obtained by directly observing oscillatory (steric) solvation forces originating simply from packing effects of the liquid particles at very small tip-sample separations d. Key to achieving this extreme sensitivity is operating the AFM in the simple variable deflection mode in the non-contact regime while specific mechanical instrumental design minimizes thermal drifts. |
